I have made these a few times before, and I think I have perfected them through trial and error. These are a fun project to do with older kids, or they make a great party favor or birthday favor to hand out to your child's classmates at school on their birthday.
Here's what you need:
Crayons (about 10 per crayon... or less if you a mini muffin pan)
Foil baking cups (They have to be the foil ones. The wax will leak through the wax paper ones.)
Paper plate or other disposable cutting surface
Preheat the oven to 225 degrees. Tear the paper off the crayons. Using the knife, cut them into small pieces.
Line the muffin pan with the foil baking cups. Fill them with the crayon pieces. Place the muffin pan in the oven and heat for 10-12 minutes. Make sure you do not overheat them, or you will end up with black crayons instead of multi-colored crayons. Ask me how I know.
Remove the pan from the oven. Let the crayons cool completely, then remove them from the pan and peel off the foil. Place the crayons in plastic bags and tie with ribbon.