I've always wanted to try this, but I haven't had the opportunity yet.
Preheat the oven to 250 degrees.
Remove the paper wrappers from the crayons and then you can either spray a mini muffin tin with vegetable oil or put the crayons into a cupcake cup and place the cup cake into a cupcake or muffin tray for support.
Allow them to melt in the oven. Melting time may vary depending on your crayons brand so make sure you watch the crayons and once they are melted take them out.
Allow them to cool completely before touching.
Now you have cool chunky crayons!