6 NEW Brass Wire Brushes 14k Gold Polishing Jewelers. This is a new set of 6 brass wire brushes on mandrels. These can be used with a Dremel tool. This can be used for polishing and producing special finishes. Can be used on copper and brass as well as aluminum and 14k gold. Each measures approximately 1 11/16" x 1" with a 3/32" shank v.