My kids love melting and making new crayons!
We actually made heart crayons around Valentine's Day.
I re-used old baby food jars to melt the crayons in. You can find ice molds and fun plastic candy molds to fill to make new fun crayon shapes!
Target usually has fun, seasonal molds like this one in their $1.00 section!
I would suggest putting the baby food jars in a pot of hot/boiling water. Then, I pour the
melted crayon into the molds. (Caution: This part is NOT OKAY for your children to do.) I know that some silicon trays are made to be put into the oven. I have not experimented to see if these trays would do well in the oven. (I might experiment with one on a really low temp. and see how it goes.)
My kids love unwrapping crayons and sorting them into the appropriate colors. Sorting things by color, shape, or size is a good skill for younger children! For older children, you can talk to the about how a solid can turn into a liquid by heating it up! (Okay, that was just the teacher in me!)
Happy Crayon Making!!