Help your young environmentalist recycle stubby crayons into new ones. First, have him separate crayons by single color or complementary shades (blues and greens, reds and yellows, etc.) and remove any paper wrappers. Put the crayon chunks into paper cups and melt them in a microwave. Then pour the mixtures into candy molds and let cool completely (you can even put them in the freezer to expedite the process). Then, flip the molds over, and gently push out.