I stripped DS down to a diaper and cover the floor and table and let him go at it. It was fun, all the newspaper went in the trash when he was done. The key is not to give them a lot of paint, just a little at a time. We did only one color at a time.
I would use washable temper paint. You can spray it with polyurithene when they are done to keep it from washing when they are outside, but no one would end up with green hair.
Re: Arts and crafts question