Steel wool comes in grades from superfine numbered 0000, 000,00,0,1,2,3,4,5,6,7 being the coarsest. I just use the 0000 (four zeros) but the machines I've had to do have no crusty stuff on them. Flitz seems to work well. Then just rub rub rub and if you have some rubber gloves wear em cause you'll want them. Sometimes I attach a buffing wheel/bob to the electric drill as well. And lotsa paper towels or rags for wiping off the black tarnish.