Gather old and broken pieces of crayons.
Once you have enough crayons, turn on the oven to preheat it to 250 degrees Fahrenheit.
Begin by removing the paper wrappers from the crayons by soaking them in a bowl of cold water for 10 to 15 minutes. The wrappers will peel off automatically, after which you can pick out the crayons and discard the water. You can also remove the wrappers without soaking the crayons but soaking is the easier way.
Break the crayons into smaller bits using a butter knife so that they can easily fit into the mould and melt properly as well.
If you have crayons of different colours, mix them thoroughly in a medium sized bowl to allow the colours to mix properly. However, if you want your heart shaped crayons to be of solid colours, separate the pieces you have according to their colors.
Fill your heart moulds with the broken crayon pieces (same colors in each mould if you don't want rainbow colored crayons).
Line your flat cookie tray with tin foil and place the heart shaped moulds over it, maintaining a distance of 2 inches between them.
Place the cookie sheet containing heart shaped moulds in the preheated oven.
Bake the crayon pieces for 15 to 20 minutes, or until they melt completely.
Once the crayons have melted completely, remove them from the oven.
Let the crayons harden before you remove them from the moulds.
Once the crayons are cool enough to handle, smooth out their rough edges by rubbing them on scrap paper.
If you are making heart-shaped crayons for a special occasion, like Valentine’s Day, stick them to a circular piece of card stock using a double sided foam tape and write your message on the card.