1 c soap flakes (from a bar of soap)
10 c water
1 Tbs glycerin
"First, grate the soap. One bar of soap yielded a little over 1.5 cups of flakes. The recipe only uses one cup of soap flakes, so I put the remaining soap in a jar for later use. In a large pot, combine 1 cup soap flakes, 10 cups water, and 1 Tbs glycerin. Turn on medium-low heat and stir until the soap dissolves. This happens fast, about a minute or two. Let the soap cool completely, then pour into the containers using the funnel. That’s all there is to it!
You can also use this soap as body wash. To make it smell nice, add a drop or two of essential oil to the mix."
Photo and Original Text Source: http://www.savvyhousekeeping.com/how-to-turn-a-bar-of-soap-into-liquid-hand-soap/