Recipes for lye soap are available at Mother Earth News and Frontier Freedom, among other websites. Lye soap is simple to make, gentle on the skin and full of glycerine. However, lye is caustic and can burn anything it touches. If making lye soap, everything the lye touches must never be used for anything else, especially for anything involving food. Wear safety glasses when making lye soap.
To make lye soap, weigh 2 pounds of lard and 4.4 ounces of lye. Pour the lye into 7 fluid ounces of water inside a glass jar placed on a surface that can handle heat. The lye and water solution becomes very hot immediately. The mixture should be stirred with a wooden or plastic spoon, then left to cool.
The next step is to heat up the lard to 90 degrees Fahrenheit in a plastic bowl. When the lye has cooled to approximately 85 degrees Fahrenheit, it can be poured into the lard slowly, while the mixture is stirred. This process takes 30 to 60 minutes. The chemical reaction between the lye and lard creates soap. After the lye and lard are mixed, essential oils can be added if desired. The lye soap can now be poured into molds.
The soap must sit in its molds for several days. Once it is hard enough to remove from the mold, cut it into bars and set them in a cardboard box lined with butcher paper. The soap needs to age for at least a month. If it leaves a slimy film upon use, it needs to cure for another week or two before using.