My mom did this when I was little as party favors for my birthday parties. She used muffin tins. I use silicone candy molds. Many more shapes, and much easier to get them out.I'm far and my little ones still use every crayon they can. What a great idea though to melt old broken crayons and form fun shapes. I will keep this in the back of my mind for when their crayon box is overfilled with broken pieces.