Brass wood-screws are usually polished in a shaking barrel about 18 in. in diameter by 2 ft. 6 in. long; the barrel is actuated by steam, or, if machine power is not available, by hand. The barrel is two-thirds filled with clean beech sawdust and the screws are put in. The friction caused by the screws coming in contact with each other and with the dust gives the polish.