One pound of coarse, ground walnut shell, (size: 8/12 or about 1/8″). Use coarse ground walnut shell in a tumbler with a pinch of powdered red rouge to put a brilliant polish on brass shell cartridges or a hand polished look on silver and gold jewelry. Use as a tumbling media on more fragile rocks, cabochons, and more. The size of the openings of the material to be tumbled determines whether to use fine or coarse ground walnut shell. You want the walnut shell to pass through the openings and not get stuck to give a nice polished finish.