A tumbler creates a high-polish finish on metal. While it’s commonly reported that tumbling work-hardens metal and wire, this is not the case; tumbling does not make a marked difference in the metal’s hardness, it only burnishes the outermost layer.
Sand your metal with progressively finer grits of sandpaper up to 600-grit. Fill the tumbler barrel 1/3 full with stainless steel shot, add a couple of drops of burnishing compound or dish soap, and cover the shot with water.
Place your jewelry in the tumbler and seal the barrel. Turn on the tumbler, and let it run for 2–3 hours. Pour the contents of the tumbler into a sieve over a sink, and rinse with cool water. Remove your jewelry and dry it. Dry the shot before storing it.