Jax Pewter Blackener All Jax metal finishing and polishing solutions are easy to use, produce authentic, consistent results, require no heat or electricity, are water-based, contain no sulfur, are non-flammable and react within seconds. Jax pewter blackener produces a dark, black antique finish on pewter, lead, brass, bronze, copper, nickel, tin-lead alloys, and solders. Available in 2 oz. and 1 pint sizes.