Homemade Soap #1 5 cups cold water 1 can lye 1/2 cup borax 1/2 cup ammonia 2 drops sassafras oil 11 cups fat To 5 cups of cold water add 1 can of lye. When lukewarm, add 1/2 cup of borax and 1/2 cup ammonia. Stir in thoroughly, then add sassafras oil for aroma. Stir in 11 cups of lukewarm fat and stir for 10 minutes until it looks like butterscotch. Pour into container and let harden for 36 hours. Cut into bars.