I've got 10 year old sweatshirts from when my Girl Scout troop used heat set crayons. They've been washed many times. We have napkins for every holiday the kids designed with those crayons. They've also been washed many time. We've got socks, bandanas, hankies, head bands......
Ummmm, yeah, well you see, my daughter went through this stage where she wanted to use those crayons to put designs on EVERYTHING!!! They really do hold up pretty well.