We made these crayon Valentine's. I saw them on Pinterest. The link took me too a flickr page with a set of photo instructions here. I went to the Dollar Store and bought 2 red silicone heart shaped muffin tins. I also bought 2 boxes of crayons. You could easily use up all of your broken crayons with this project. Daddy and Kaylee peeled the wrappers off the crayons and then Daddy cut them up into various sizes of pieces. We took out the black ones and didn't use very many of the brown because I wasn't sure how they would spread once in the oven. Kaylee and I put even amounts of each color into the tins. You don't have to fill the tins, as long as the bottom is covered. Once we got all the pieces in ours were about half full. Into the oven at 230°F for 15 minutes. Let them cool and then remove from silicone tins. Marvel at their waxy goodness!!! I printed the cards from the blog The Long Thread. I did use my corner punch to round the edges. I used pop dots to attach my crayons to the cards. Because the back of the crayon is not completely flat you will need to be creative to attach them to the cards. That's why the pop dots worked. I made 12 of them and Kaylee took 6 to Sunday School. She was so excited when there were only 5 other kids so got to bring home one of her own Valentine's!
My lessons learned: use real crayons. I bought the cheap ones that don't color very well and the kids instantly wanted to use their hearts to color. They don't color very well. But they would if we had used the real crayons. We put our silicone tins, which were very squishy, on a cookie sheet to make it easier to put them in and out of the oven. You could easily choose whatever colors you wanted to include for crayons too.