Don't know what to do with all those broken crayons?!
Get a silicon oven proof mold. Remove any existing paper from the crayons then break them up into really little pieces. Fill the molds, slightly over filling them. Place on a normal baking tray (this will make getting the mold out of the oven much easier) in a moderate oven and bake for around ±10min. Once melted, carefully remove from the oven and let cool before popping them out of the mold. Then voilà, new usable crayons for the kids!