Give new life to worn-down crayons. Remove paper from about 20 crayons and seal them in a gallon-size, zip-top plastic bag. Break them up using a hammer. Place 2- to 3-inch cookie cutters onto a parchment-lined cookie sheet. Your kid can fill the cutters with a ½-inch layer of crayon pieces, then place the sheet in direct sunlight until the pieces melt (three to six hours). Let cool for one hour or until solid, then gently pop out of cutters.