The box says: "A slight film of oil has been used to protect Slinky. If slightly sticky, wipe off with a clean cloth." This is an understatement - I had to take these away from the kids because their hands were all greasy/oily with black oil after they played with these and then they would leave black hand marks on the walls.Maybe you can try washing these, but I would personally stay away from this one if you are intending to play with it.