Brass brushes are non-sparking and softer than steel. They will not scratch soft metals like gold , copper, brass. -Ideal for cleaning and surface-finishing items -For use on items made from gold, bronze, copper or brass -Use a brass brush to create a soft, satin or matte finish -Very effective on flat surfaces and in hard-to-reach areas like slots (User Tips) Keep a light touch, letting the tips of the brush do the work. Too much pressure can break the wire bristles. Before using on a material, allow the tool with brush to run at operating speed for at least one minute to discharge any loose wire bristles. Make sure no one stands in front of or in line with the brush. SAFETY: Do not run in excess of 15,000 rpm.