This is the soap mix I use: I run the bars through a food processor or grate it so it dissolves easier. 1 bar Ivory soap, 1 bar Castile soap, 2 oz. glycerin, 3 1/2 cups water. Heat the water but do not boil and melt in soap. Pour into a rubbermaid container and let cool over night. Keep a lid on the mix so you don't loose the moisture. You do not want to use oil or fat because you will not be able to re-moisten string if needed.