We actually did KarrieT's suggestion this year. A few pointers though.... I thought we had a LOT of broken crayons but you actually need quite a bit. I learned that the hard way because I actually had to go out and buy a box of crayons to finish the project. That being said, about 24 crayons make 10 hearts. The 2nd box I bought, I bought the cheaper, non washable crayola crayons. The non washable ones tend to melt better I found. Don't leave them in too long or the get a murky coating on top.
My kids helped me take off the wrappers but it was MUCH harder than I remember as a child. The wrappers would not come off.Somy husband slit each crayon with a swiss army knife before passing the crayons to the kids at the other end of the table. The first batch I used a knife and cutting board but it did a number on my knife and cutting board. 2nd batch, I let my kids break the crayons and I used a cheaper pair of scissors (to speed it up). They helped fill up the cups too so it was definitely a joint project. Once complete, I put the crayons into small bags and tied them with ribbon. I then created a little Valentine's quote "You Color My World __________ Happy Valentine's Day. Made with love by ______" I printed them up on circle labels. The kids put the labels on the bags. When we were at the last label, my daughter said "Where's Misss _____ and Miss _____ labels" Ooopss. Off to buy more crayons - I forgot the teachers - the most important Valentine's!!!
I have also seen these same hearts stuck on square pieces of paper with a Valentine note. It is a great project to do with kids with some tweaking.