How to use Bar Soap Nubs, continued...
We put the grated soap into a double boiler with some of the "melt and pour" soap. "Irish Spring" and similar commercial bar soaps don't melt. The "melt and pour" soap serves as glue to hold the grated commercial bar soaps together. How much of the "melt and pour" to use? For this batch (about 6 lbs of grated soap), I used 4 lbs of "melt and pour". Could have gotten by with less.
Give the double boiler time to heat the mixture thoroughly. Be prepared to have your kitchen "...smell as fresh as an Irish spring!" You should be able to ladle the melted soap into a soap mold without difficulty. You may have to add more "melt and pour" if the soap goop in the double boiler is too thick.
Once the molds are filled, let them cool enough that the bars don't deform when you demold. Once they are out of the mold, trim the bars with a sharp knife, and throw the trimmings back in the pot! I wrap the finished bars in plastic wrap.