Play doh, silly puddy, paint, slime, and other non solid toys. Just realize that there is a certain age that you can trust your children with such material. That age is somewhere around the point where they can enlist in the military. They are marketed as toddler toys. They finger paint, mold models, and mix colors until everything is brown. This is art. Based on what I’ve seen in museums, my kids could skip the 18 years of screwing life up and wasting money on art college, and sell direct. It would start cheaper, but as their name gains recognition, I could retire off the proceeds. Either way, I’ve found remnants of future Rodin or Van Gogh masterpieces in the carpet, the couch, and other places. While I’m all for the arts and encouraging creative behavior, there have to be boundaries on the moldable/stainable materials. I say keep it to the kitchen table and build a wall to keep it off the carpet.