If my silicone molds have a lot of wax on them, I put them upside on a foil lined cookie sheet in the oven. Then I wash them with hot soapy water. Let dry competely. Then I can use them for m & p soap. If not alot of wax, then I use my heat gun to melt the wax, wipe it out with a paper towel and then wash in hot soapy water.