Do like this: Remove all paper from your crayons / crayon nubs. Cut the crayons into small pieces with a knife. Fill your optional silicone mold (or other suitable oven-safe mold) with the crayon crumbs. Place the mold in the oven at 400°F (200°C) for about 5-10 minutes, until the crayons have melted. Place close attention. Be sure not to burn yourself when removing the mold from the oven! Another tip (which I read at Homemade by Jill) is to first melt the crayons in an empty tin can in water bath and then pour the “batter” into the molds.