Sandpaper t-shirts

I was looking for a few fun, crafty projects for my 4 and 5 year old to do during spring break. Like most things, I turned to Pinterest. This is one of the ideas I decided upon. We already had a couple of fairly new white T-shirts and of course we have crayons, so all I had to purchase was sandpaper. I paid about $3.00 for a pack of 5, and I used half a sheet for each shirt. So I have enough left for other projects.
My kids loved doing this. We made two mistakes. They did not make them dark enough, and my oldest decided to write some words. The problem is, you have to color the sandpaper really dark in order for it to transfer really dark. And of course, once you put the sandpaper on the shirt, it made the writing backwards. That was my mistake.
But it worked really well and my girls had fun doing it.