In the vast expanse of human history, soap has been a humble yet indispensable ally in our quest for hygiene and health. Did you know that the ancient Romans were so fond of their soap that they named it ‘sapo’, which later evolved into the word we use today? Or that during the 19th century, a lack of soap contributed to the spread of diseases like cholera and typhoid, leading to millions of deaths worldwide? Today, soap is ubiquitous, but what if the world as we know it changed? What if the supply chains that bring us our favorite brands of soap were disrupted, and we were left to fend for ourselves? This is where the art of survival soap making comes into play.
Agree with me when I say that in a post-collapse world, hygiene would be more important than ever. Promising you that this article will not only guide you through the process of making your own lye soap but also introduce you to a world of natural cleansers and DIY hygiene products. You’ll learn how to harness the power of nature to keep yourself clean and healthy, even when the going gets tough.
So, let’s dive into the fascinating world of survival soap making. In this comprehensive guide, you’ll discover the science behind soap, the various natural ingredients you can use, and step-by-step instructions to create your own bars of lye soap. By the end of this article, you’ll not only have the knowledge to make your own soap but also a newfound appreciation for this ancient art. So, grab your apron, and let’s get started!
Mastering Natural Cleansers for DIY Hygiene Products
Embarking on a journey to master natural cleansers for DIY hygiene products is like stepping into a lush, green garden of possibilities. Imagine transforming your bathroom into a sanctuary filled with the invigorating scents of essential oils and the comforting knowledge that you’re using ingredients straight from nature’s pantry. This adventure begins with understanding the power of simple, everyday items like lemons, vinegar, and baking soda. These humble ingredients, when combined with a dash of creativity and a sprinkle of science, can replace a multitude of store-bought products, saving you money and reducing plastic waste. From creating your own all-purpose cleaner to whipping up a batch of invigorating shower gel, the process is not only rewarding but also a fun experiment in chemistry. So, let’s roll up our sleeves, don our aprons, and dive into the world of natural cleansers. Who knows, you might just discover your inner alchemist!
The Importance of Hygiene in a Post-Collapse World
In the wake of a societal collapse, maintaining hygiene becomes not just a matter of personal cleanliness, but a critical factor in survival. A post-collapse world, with its disrupted infrastructure and potential scarcity of resources, can be a breeding ground for diseases. This is where the humble art of soap making can play a pivotal role.
The importance of hygiene in such a scenario cannot be overstated. It’s our first line of defense against pathogens that cause illnesses like diarrhea, respiratory infections, and even deadly pandemics. Regular handwashing, for instance, can reduce the risk of these diseases by up to 50%.
Soap, a simple yet powerful cleaning agent, is our primary tool for maintaining hygiene. However, in a post-collapse world, access to store-bought soap might be limited. This is where knowing how to make soap can be a lifesaver. It’s a skill that ensures a steady supply of cleaning agents, reducing the risk of disease and keeping your community healthy.
Making soap involves a few simple steps. First, you’ll need a source of fat, like lard or tallow, and a source of lye, which can be made from wood ashes. You’ll also need a heat source and something to mix and mold the soap in. The process involves heating the fat, adding the lye, mixing until it reaches ‘trace’ (a stage where the mixture thickens and leaves a trace on the surface), then pouring it into molds to set.
But soap making isn’t just about personal hygiene. It also plays a crucial role in maintaining cleanliness in your living space and on your tools. Cleanliness can prevent the spread of diseases like typhus, which can be carried by lice, and cholera, which can be spread through contaminated water.
Moreover, soap making can be a valuable skill to barter with. In a post-collapse world, knowledge and skills can be as valuable as gold. Knowing how to make soap can help you trade for other necessities, like food or medicine.
In conclusion, hygiene is not a luxury in a post-collapse world; it’s a necessity. And soap making, a simple, ancient skill, can ensure that you have the cleaning agents you need to maintain that hygiene. It’s a skill worth learning and preserving.
Understanding Lye: The Key Ingredient in Soap Making
Understanding Lye: The Key Ingredient in Soap Making
At the heart of every bar of soap lies a humble yet powerful ingredient: lye. This versatile substance, also known as sodium hydroxide, is the unsung hero of soap making, responsible for the chemical reaction that transforms oils into a cleansing, solid bar. But what exactly is lye, and how does it work its magic?
Lye is a strong alkaline substance, typically produced by leaching wood ashes with water. It’s a powerful base, with a pH that can reach up to 14, making it highly reactive. This reactivity is what makes lye so essential in soap making. When combined with oils, lye triggers a process called saponification, where the triglycerides in the oils react with the lye to form soap molecules and glycerin.
However, it’s crucial to understand that lye is not the same as other alkaline substances like baking soda or washing soda. While they share some similarities, such as their ability to raise the pH of a solution, they differ significantly in their strength and reactivity. Baking soda, for instance, is a weak base, while washing soda is stronger but still not as potent as lye. This is why lye is the preferred choice for soap making, as it can effectively saponify oils and create a hard, long-lasting bar.
Safety is paramount when handling lye. It’s highly caustic and can cause severe burns if it comes into contact with skin or eyes. Therefore, it’s essential to wear protective gear, including gloves and eye protection, when working with lye. Always add lye to water, not the other way around, to prevent the lye from splattering. After use, clean up any spills immediately and dispose of lye according to local regulations.
Once you’ve made your soap, proper storage is crucial. Lye itself doesn’t go bad, but soap made with lye can degrade over time if not stored properly. Keep your soap in a cool, dry place, away from direct sunlight and heat sources. This will help maintain its quality and longevity.
In conclusion, lye is a fascinating and powerful ingredient in soap making. Understanding its chemistry and how to handle it safely is key to creating high-quality, long-lasting soap. So, the next time you reach for a bar of soap, remember the incredible chemical reaction that turned humble oils into a cleansing, solid bar, all thanks to the mighty lye.
Gathering and Preparing Natural Oils for Soap Making
Embarking on the journey of soap making with natural oils is an enriching experience that allows you to harness the power of nature’s bounty. Let’s delve into the process of sourcing and preparing three versatile oils: coconut, olive, and palm oil. Each oil brings its unique properties and benefits to your handmade soaps.
The first oil on our list is coconut oil, a tropical treasure that solidifies below 76°F (24°C). It’s rich in lauric acid, which creates a hard, long-lasting bar with big, fluffy lather. To prepare, melt the oil gently, ensuring it doesn’t exceed 120°F (49°C), as high temperatures can degrade its beneficial properties.
Next, we have olive oil, a liquid gold at room temperature, thanks to its high oleic acid content. It’s gentle on the skin and adds conditioning properties to your soap. When preparing, ensure the oil is fresh and of good quality to avoid any off-putting scents in your final product.
Lastly, let’s not forget palm oil, a versatile ingredient that helps create a stable, hard bar. It’s high in palmitic acid, which contributes to a long-lasting lather. When sourcing, opt for sustainable palm oil to support eco-friendly practices. To prepare, melt it gently, just like coconut oil.
Now that we’ve discussed the oils, let’s briefly explore their benefits:
- Coconut oil: Hard bar, big lather, cleansing
- Olive oil: Gentle, conditioning, moisturizing
- Palm oil: Stable, hard bar, long-lasting lather
Combining these oils in your soap recipe allows you to create a balanced, nourishing bar that’s a true reflection of nature’s generosity.
The Saponification Process: Turning Oils into Soap
The art of soap making, dating back to ancient civilizations, is a fascinating process that involves a chemical reaction known as saponification. This process transforms oils and fats into soap, a substance that’s not only useful for cleaning but also a delight to create. Let’s dive into the step-by-step chemical process of saponification and explore a simple recipe for beginners.
The saponification process begins with triglycerides, the scientific term for oils and fats. These are composed of three fatty acid chains attached to a glycerol molecule. When triglycerides react with a base, typically sodium hydroxide (lye) in the case of bar soap, or potassium hydroxide for liquid soap, a chemical reaction occurs. This reaction is exothermic, meaning it produces heat, and results in the formation of soap molecules and glycerin.
Soap molecules are composed of a fatty acid chain attached to a sodium or potassium ion, depending on the base used. Glycerin, a byproduct of saponification, is a valuable humectant, often collected and used in skincare products due to its moisturizing properties.
Now that we understand the science behind saponification, let’s explore a simple soap recipe for beginners. This recipe uses the hot process method, which is more forgiving for new soap makers.
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Ingredients:
- 100g Coconut Oil
- 100g Olive Oil
- 100g Palm Oil
- 130g Distilled Water
- 40g Sodium Hydroxide (Lye)
- Essential Oils for fragrance (optional)
Equipment:
- Safety gear (gloves, long sleeves, and eye protection)
- Stainless steel pot
- Stainless steel spoon
- Digital scale
- Two heat-resistant plastic containers
- Immersion blender
- Soap mold
- Stick blender (optional)
Instructions:
1. Begin by safely handling the lye. Weigh out 40g and slowly add it to the distilled water (130g) in a well-ventilated area. Be cautious as this will create heat and fumes. Stir until the lye is fully dissolved.
2. In a stainless steel pot, weigh out and combine the coconut oil (100g), olive oil (100g), and palm oil (100g). Heat gently until the oils have melted and reached a temperature of around 120°F (49°C).
3. Once both the lye solution and the oils have reached approximately 120°F (49°C), slowly pour the lye solution into the pot containing the oils. Use your immersion blender to mix the two until ‘trace’ is reached. This is when the mixture thickens and leaves a trace or imprint on the surface when drizzled.
4. At light trace, add your essential oils for fragrance, if desired. Mix well.
5. Pour the soap batter into your prepared mold, smoothing the top with a spatula.
6. Cover the mold with a lid or some insulation to keep it warm while the saponification process occurs. Allow the soap to sit undisturbed for 24 hours.
7. After 24 hours, you should see that the soap has hardened and is ready to be unmolded. Remove the soap from the mold and cut it into bars.
8. Allow the bars to cure for at least 4 weeks. This allows excess water to evaporate, resulting in a harder, longer-lasting bar of soap.
9. Enjoy your handmade soap! Remember, soap making is both an art and a science. Don’t be discouraged if your first few batches aren’t perfect. With practice, you’ll develop a feel for the process and create beautiful, functional works of art.
Adding Exfoliants and Colorants to Your Soap
Adding a touch of nature and a pop of color to your homemade soaps can transform them into little luxuries that pamper your skin and delight your senses. Let’s dive into the world of exfoliants and natural colorants, and learn how to safely incorporate them into your soap-making journey.
Exfoliants like oatmeal, coffee grounds, or sugar are not just fun additives, but they also bring a host of benefits to your soap. Oatmeal, with its gentle, soothing properties, is perfect for sensitive skin. It’s rich in polysaccharides that help lock in moisture, leaving your skin feeling soft and supple. Coffee grounds, on the other hand, are a great source of antioxidants that can help fight free radicals and reduce the appearance of aging. They also provide a gentle exfoliation, helping to remove dead skin cells and unclog pores. Sugar, with its fine texture, is an excellent exfoliant for all skin types. It helps to slough off dead skin cells, revealing smoother, brighter skin.
To incorporate these exfoliants into your soap, you can add them at the ‘trace’ stage, which is when your soap batter has thickened to the consistency of pudding. Here’s a simple step-by-step guide:
- Prepare your soap batter according to your recipe.
- Once you’ve reached trace, add your exfoliant. A good rule of thumb is to add about 1-2 tablespoons of exfoliant per pound of soap.
- Mix well to ensure the exfoliant is evenly distributed throughout the batter.
- Pour your soap batter into your mold and let it set.
Now, let’s talk about adding a splash of color to your soap. Natural pigments can not only make your soaps look beautiful but also provide additional skin benefits. For example, turmeric is a natural antiseptic and can help brighten the skin, while spirulina is rich in nutrients that can nourish and moisturize the skin.
To safely color your soap using natural pigments, you can either add them directly to your soap batter or make a colorant paste. Here’s how:
- For direct addition, simply mix your pigment powder into your soap batter at trace. Start with a small amount, like 1/4 teaspoon, and increase as desired. Keep in mind that natural pigments may not be as vibrant as synthetic ones.
- For a colorant paste, mix your pigment powder with a small amount of liquid oil, like olive oil or sunflower oil. This helps to disperse the pigment evenly in the soap batter. Add this paste to your soap batter at trace.
Remember, when working with natural pigments, it’s always a good idea to do a patch test first to ensure you don’t have any adverse reactions. Also, keep in mind that natural pigments may fade over time, especially when exposed to light and heat.
So, go ahead, experiment with different exfoliants and natural pigments. Your skin will thank you, and you’ll have a blast creating beautiful, unique soaps that are as good for your skin as they are for your soul!
Curing and Storing Your Homemade Soap
Curing and storing your homemade soap is a crucial step that ensures its longevity and quality. The curing process, which typically takes about 4 to 6 weeks, allows the soap to dry out and harden, making it milder and longer-lasting. This is because soap is made through a chemical reaction called saponification, where oils and lye combine to form soap and glycerin. During this process, some lye remains unreacted, and curing helps to evaporate excess water and lye, making the soap gentler on the skin.
The ideal curing environment is a cool, dry, well-ventilated area, away from direct sunlight. You can place your soap on a rack or a flat surface, ensuring they don’t touch each other to allow air to circulate freely. Here are some tips to maintain the quality and longevity of your homemade soap:
- Avoid Humidity: High humidity can cause your soap to sweat, leading to a slimy surface and reduced shelf life. Keep your soap in a cool, dry place with a relative humidity of less than 50%.
- Avoid Heat: Heat can melt your soap, especially if it contains high amounts of coconut oil or other soft oils. Store your soap in a cool place, away from heat sources like radiators or direct sunlight.
- Avoid Moisture: Keep your soap away from water or moisture. This includes avoiding steamy bathrooms or kitchens. If your soap gets wet, allow it to dry completely before using or storing it again.
- Use an Airtight Container: Once your soap is completely cured, you can store it in an airtight container to protect it from dust and other contaminants. However, ensure the container is not completely sealed to allow some air circulation.
By following these tips, you can extend the life of your homemade soap, ensuring it remains fresh, fragrant, and effective for as long as possible.
Troubleshooting Common Soap Making Issues
Embarking on the journey of soap making can be an incredibly rewarding experience, but it’s not uncommon for beginners to encounter a few bumps along the way. One of the most perplexing issues is when your carefully crafted soap refuses to harden, leaving you with a gloopy mess. This is often due to not allowing the soap to set long enough after mixing, or using too much water in your recipe. To avoid this, ensure you’re patient and let the soap set in the mold for at least 24 hours before unmolding, and keep an eye on the water content in your recipe.
Another common issue is soap that’s too soft. This can be due to a few reasons, such as using too much soft oil in your recipe, not allowing the soap to cure properly, or not reaching trace. To troubleshoot this, make sure you’re using a balance of hard and soft oils in your recipe, allow your soap to cure for at least 4-6 weeks to evaporate excess water, and ensure you’ve reached a thick trace before pouring your soap into the mold.
Lastly, a lack of lather can be quite disappointing. This can be due to using too much hard oil in your recipe, not using enough superfat, or not allowing the soap to cure properly. To troubleshoot this, ensure you’re using a balance of hard and soft oils, add enough superfat to your recipe to ensure a good lather, and allow your soap to cure properly to ensure all the water has evaporated.
Remember, soap making is a craft that requires patience and practice. Don’t be disheartened if you encounter a few issues along the way. Each problem is an opportunity to learn and improve your skills. Happy soap making!
Expanding Your Soap Making Skills: Advanced Techniques
Embarking on the journey of advanced soap making is an exciting venture that allows you to explore new techniques and create stunning, unique bars. Let’s delve into three captivating methods: rebatching, swirling, and layering. Each technique offers a world of possibilities, so let’s dive in!
Rebatching: A World of Possibilities Rebatching, also known as ‘melt and pour,’ is an advanced technique that allows you to create intricate designs and patterns in your soap. It involves melting down existing bars of soap and adding new fragrances, colors, or additives. Here’s a simple recipe to get you started:
- Melt down 2 lbs of your favorite soap base in a double boiler.
- Once melted, add 1 oz of your desired fragrance oil and mix well.
- Pour the mixture into a mold and let it set for a few hours.
- Once set, remove the soap from the mold and cut it into small pieces.
- Melt the pieces in a double boiler again, adding new colors, exfoliants, or other additives as desired.
- Pour the mixture into a new mold and let it set for a few hours before unmolding.
Swirling: Art in Every Bar Swirling is an advanced technique that allows you to create beautiful, marbled effects in your soap. Here’s a simple recipe to create a stunning swirl:
- Prepare two batches of soap at the same trace level.
- Divide the soap into two containers and color each with a different colorant.
- Pour one color into the mold, then pour the second color on top, creating layers.
- Use a spoon or a chopstick to swirl the colors together, creating a marbled effect.
- Tap the mold on the counter to remove any air bubbles and let it set for a few hours before unmolding.
Layering: A Symphony of Colors Layering is an advanced technique that allows you to create beautiful, multi-colored bars of soap. Here’s a simple recipe to create a layered effect:
- Prepare multiple batches of soap at the same trace level.
- Divide each batch into separate containers and color them with different colorants.
- Pour the first color into the mold, filling it about 1/4 inch.
- Let the soap set for a few minutes, then pour the next color on top, creating a new layer.
- Repeat this process until you’ve reached your desired number of layers.
- Tap the mold on the counter to remove any air bubbles and let it set for a few hours before unmolding.
Each of these techniques offers a wealth of possibilities, allowing you to create unique, stunning bars of soap. So, grab your apron, and let’s get started! Remember, practice makes perfect, so don’t be afraid to experiment and have fun with your creations. Happy soaping!
Soap Making for Camping and Survival Kits
Embarking on a camping trip or preparing a survival kit often involves meticulous planning, ensuring you have all the essentials to navigate the great outdoors safely and comfortably. One often overlooked yet crucial item is homemade soap. Including soap in your camping and survival kits is not just a matter of hygiene, but a matter of health and safety.
Soap is a vital tool for removing dirt, grease, and germs from your hands, face, and body. In a camping or survival situation, maintaining cleanliness is paramount to prevent infections and illnesses. For instance, proper handwashing can significantly reduce the risk of foodborne illnesses, while keeping your body clean can help prevent skin infections and rashes.
Moreover, homemade soap can serve other purposes in a pinch. It can be used to wash dishes, clean clothes, or even as a makeshift shampoo. Some soaps, like those made with certain essential oils, can also act as a natural insect repellent or antiseptic.
Making your own soap for camping and survival kits offers several advantages. It’s cost-effective, allows you to customize the ingredients to suit your needs and preferences, and ensures you have a reliable source of soap even if commercial supplies run out. But how do you make soap that’s easy to pack and use on the go?
Firstly, consider the size and shape of your soap. Bars that are too large can be bulky and heavy, while those that are too small may not last long. A good compromise is a bar that’s about the size of a standard hotel soap, around 3-4 ounces. You can also make your soap into smaller, individual use pieces that can be easily packed and used.
Next, think about the ingredients. While there are many recipes for homemade soap, for camping and survival kits, simplicity is key. A basic soap made with lye, water, and a single oil like coconut or olive oil can be effective and easy to make. You can also add essential oils for scent and additional benefits.
Lastly, consider the packaging. Wrap your soap in a waterproof material like wax paper or plastic wrap to keep it dry and prevent it from melting or becoming a gooey mess in your kit. You can also place it in a small, airtight container for added protection.
In conclusion, including homemade soap in your camping and survival kits is a smart and practical move. It’s a small item that can make a big difference in maintaining your health and comfort in the great outdoors. So, why not give it a try? It’s easier than you think, and your future self will thank you!
Teaching Soap Making to Others: Passing on a Valuable Skill
Soap making, an ancient craft that’s both art and science, is a skill worth sharing. As you’ve mastered the lye, learned the swirls, and created bars that cleanse and delight, it’s time to pass on your knowledge to others. Teaching soap making isn’t just about sharing a hobby; it’s about empowering others to create their own cleaning products, reduce waste, and indulge in a little DIY therapy.
Safety is paramount when teaching soap making. Before you begin, ensure your students understand the basics of handling lye, a strong alkali that can cause serious burns. Here are some safety tips to keep in mind:
- Always wear gloves, long sleeves, and safety glasses when handling lye.
- Keep lye away from heat, water, and other chemicals until ready to use.
- Never add water to lye; always add lye to water.
- Have a first aid kit on hand, just in case.
Now, let’s dive into the fun part
- teaching the actual soap making process. Start with the basics: understanding the ingredients (lye, water, oils, and fragrances), the equipment needed (mixers, molds, scales, etc.), and the process itself (mixing, pouring, and curing).
Encourage your students to experiment with different oils, scents, and techniques. The beauty of soap making lies in its creativity. You might want to demonstrate a few techniques, like swirling, layering, or embedding, and let your students try them out.
Remember, teaching is a two-way street. Be open to learning from your students too. They might have ideas or techniques that you hadn’t considered. And who knows, you might just fall in love with a new soap recipe or technique yourself!
So, go ahead, share your soap making knowledge. You’re not just teaching a skill, you’re fostering a community of creators, reducing waste, and spreading a little bit of joy, one bar at a time.
FAQ
What is lye soap and why is it important in a post-collapse world?
What are some natural cleansers that can be used as alternatives to store-bought soaps?
- Castile soap: Made from plant oils like olive, coconut, or palm, castile soap is a gentle yet effective cleanser.
- Soap nuts: These are the dried shells of the soapberry tree. When boiled in water, they create a natural surfactant that can be used as a soap.
- Horsetail: This plant is rich in silica and can be used to make a natural soap or added to other soaps for extra cleansing power.
- Baking soda: A versatile cleaning agent, baking soda can be used to make a simple soap or added to other soaps to boost their cleansing abilities.
How do I make lye soap at home?
- First, calculate the amount of lye and water you’ll need. A general rule is 39% lye to water by weight. For example, if you’re using 100g of lye, you’ll need 261g of water.
- Next, put on safety gear, including gloves and eye protection, and slowly add the lye to the water. Never add water to lye, as it can cause a dangerous reaction.
- While the lye is dissolving, melt your fat or oil in a separate container. You can use animal fats, vegetable oils, or a combination of both.
- Once the lye has fully dissolved, let both the lye water and the oil cool to around 120-130°F (49-54°C).
- Slowly pour the lye water into the oil, then use an immersion blender to mix until ‘trace’ is reached. This is when the mixture thickens and leaves a trace or imprint on the surface.
- Add any essential oils, herbs, or other additives at light trace, then pour the soap into a mold and let it set for 24 hours.
- After 24 hours, remove the soap from the mold and cut it into bars. Let the bars cure for 4-6 weeks to allow excess water to evaporate, then they’re ready to use.
What are some DIY hygiene products I can make besides soap?
- Toothpaste: A simple toothpaste can be made by mixing baking soda with water or coconut oil. You can also add essential oils for flavor and additional benefits.
- Deodorant: A natural deodorant can be made using ingredients like baking soda, cornstarch, coconut oil, and essential oils. This can help control odor without the use of harsh chemicals.
- Shampoo: A simple shampoo can be made using ingredients like castile soap, water, and essential oils. This can help clean your hair without stripping it of its natural oils.
- Hand sanitizer: A basic hand sanitizer can be made using isopropyl alcohol, aloe vera gel, and essential oils. This can help kill germs when soap and water aren’t available.
How can I ensure the safety of my DIY hygiene products?
- Always wear appropriate safety gear, including gloves and eye protection, when handling lye or other harsh chemicals.
- Never add water to lye. Always add lye to water to prevent dangerous reactions.
- Keep your workspace clean and free of clutter to prevent accidents.
- Store your DIY hygiene products in a cool, dry place away from heat sources and direct sunlight.
- Always test new products on a small patch of skin before using them extensively to ensure you don’t have an adverse reaction.
- Label your products clearly with their contents and the date they were made to avoid confusion or accidents.
- When in doubt, consult reliable sources for guidance on safe handling and storage of ingredients.
Can I use my DIY hygiene products if I have sensitive skin?
- Use gentle ingredients like castile soap, oatmeal, or aloe vera in your products.
- Test new products on a small patch of skin before using them extensively.
- If you experience irritation, discontinue use and try a different recipe or ingredient.
- Consider using products with fewer ingredients to reduce the risk of allergic reactions.
- If you have a known skin sensitivity, avoid using ingredients that could exacerbate it.
Always remember that everyone’s skin is unique, so what works for one person might not work for another.
How can I preserve my DIY hygiene products for long-term storage?
- Store your products in a cool, dry place away from heat sources and direct sunlight.
- Use airtight containers to prevent moisture and contaminants from entering.
- Label your containers with the product name, date made, and expiration date (if applicable).
- Rotate your stock to ensure you’re using the oldest products first.
- For products with a short shelf life, like fresh ingredients or homemade lotions, consider making smaller batches more frequently.
- For products with a long shelf life, like soap or toothpaste, consider making larger batches to save time and resources.
Regularly inspect your stored products for signs of spoilage or contamination, and discard any that show signs of deterioration.