Lye is a key ingredient in soap making. Whether the sodium hydroxide form for solid bars or potassium hydroxide for liquid soap, lye causes the soap to lather when in contact with water and binds all of the soap's ingredients together. If you make soap at home with lye, it can be especially corrosive if it comes in contact with your skin. You can make soap without pure lye, but some of the substitutes will still contain traces of the caustic ingredient.
You can make soap at home using glycerine bars, which still contain lye but are much safer for your skin. The process involves melting glycerine in a crock pot or double boiler and adding cocoa butter, essential and fragrant oils and colouring agents if you desire. After stirred and melted together, the mixture is poured into moulds to form into bars of soap.
You can make homemade soap through rebatching, which involves using a rebatching kit, a rebatching soap base or incorporating partially used bars of soap. These bases naturally also contain lye but are much safer to work with than a pure lye ingredient. Again, the base is melted. Milk, sweet almond oil and fragrant and essential oils are added and stirred. The mixture is then poured into moulds to form bars of soap as with a glycerine-based recipe.
Soap nuts are not actually nuts, but berries that grow on trees. They were first discovered as effective natural ingredients for cleaning laundry. You can also use them to make a homemade liquid hand soap without any products containing lye. Simply add one or two dried berries to warm water in a spray-pump bottle. The bottle will cause the mixture to form a slight soapy lather for when you wash your hands.
Often commercial dishwasher detergents contain a form of lye. You can make a homemade dishwasher powder without using any lye products, says Binghamton University. Mix 1 part borax to 1 part baking soda and store in an airtight container. You only need approximately 2 tbsp of this powder mixture per dishwasher load. Binghamton University also recommends adding vinegar to the rinse slot of the dishwasher.