First, fill a greased silicon mold -- this one is of snowflakes -- with broken, wrapper-free crayons. Note: taking those wrappers off can take a looong time. It might make a good mindless task to do while watching a Christmas special on television, say.
Put them in an oven preheated to 300 degrees Fahrenheit for ten minutes, then stir them gently with a skewer. Repeat again in five minutes or so and again until the crayons are completely melted. Remove from the oven and let them cool. When they have started to set, stick a skewer through each ornament to make a hole.
Pretty, aren't they? Use a darning needle to stick thread through the hole in each ornament for hanging.
We got the idea from Twelve Crafts Until Christmas, who kept the colours a bit more separate -- a look I prefer and Luke wasn't particularly interested in achieving. Twelve Crafts also made enough for the 22 kids in her daughter's class. That was my intention, too, but these require a LOT of crayons. Next time I think I'd use smaller molds. We ended up with six, which we put on our own tree.