These are a great idea for Valentine's Day. We made them for my daughter to take to class and all the kids loved them too!
We used a combination of the tutorials from The Long Thread and from Make and Takes as well as some trial and error of our own.
My daughter had a great time breaking up the old crayons and dividing them among the different spaces in the silicone pan we bought. It was really easy to pop the cooled crayons out of the silicone pan and it was pretty easy to clean up afterwards too. We did put the pan on a cookie sheet so it was easy to get in and out of the oven because the silicone was bendy.
They were a hit with both teachers and kids and we would absolutely make these again.