Safe paint for the Kids to paint my CT

I dont care to get any wrap, i like the silver on my CT, I have little kids and I think them and their friends should just paint the CT any way they like... I have a feeling if I dont choose the right paint, it may leave that "always there" residue after I wash it off. You guys think there is a paint out there that I can use that would stay decently in place but not leave a residue after gone???