These plastic replicas of walnut shells are perfect for doing a 3-shell game demo. They are
lightweight, apparently indestructible, and after some preparation (sanding), they glide smoothly
over any surface. And they handle a soft pea beautifully. I painted mine brown to make them look
more realistic, and also to make them easier to grip. Out of the box they are a bit slippery.
I also sanded my shells as they were catching the fibers of my close up pad.
If you sand them lightly and just want to touch in the paint on the bottom/edges, I used model paint for Warhammer miniatures - Citadel "Averland Sunset" and it's a very close match to the stock color.