Use a rubber mold. This one is from IKEA.
The hardest part is peeling the crayons. Yep! I offered the job to my kiddos at recess time!
Using a meat tenderizer, I was able to get smaller pieces to fill in the gaps.
Put into the oven at 320 degrees for 10-15 minutes.
Allow to cool completely...
Viola! Recycled, super cute heart crayons! Add a little typed valentine message and you have a Valentine hit!