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How to Clean Rust Spots From Bronze

Karie Lapham Fay

Bronze does not really rust. "Rust" is an appropriate term for iron-based metal objects only, as John Christie explains on the Mad Science Network. Rust appears as a result of the interaction of air with the chemical properties of iron. "On copper, bronze, or silver, we talk about a 'tarnish' if we are thinking about the degradation of the metal surface, or a 'patina' if we are thinking about the pretty and sometimes artistic effects" of this same process, Christie notes. Bronze, an alloy of copper and tin, normally reacts very slowly and produces a tarnish that eventually turns green. It is fairly easy to clean and prevent.

Use a toothbrush to clean the tarnish in hard-to-reach areas on bronze.
  1. Remove any existing lacquer finish on the bronze item you are cleaning. Lacquer is often applied to decorative bronze items as it provides a clear, protective finish. Open the windows and turn on fans in your work area to provide ventilation before beginning -- chemical lacquer removers produce strong fumes.

  2. Pour enough acetone into a bucket, sink or any container large enough to hold your item (if not possible, then apply with a clean cloth). Use a toothbrush or other soft-bristled brush to scrub gently -- harsh scrubbing or scrubbing items may damage the bronze. Rinse thoroughly when complete.

  3. Mix acetic acid (vinegar) with baking soda. Allow the solution to bubble, then blend into a thick paste. Exact amounts are unimportant.

  4. Apply a small amount of paste with your finger to your bronze item, using gloves to protect your hands. Rub it in using a clean cloth or toothbrush and working in either a circular motion or with the natural design to avoid scratching (remember bronze is a soft metal). Continue applying across the entire item.

  5. Allow the paste to set on the item for a minimum of 30 minutes. Work the paste into the bronze again before rinsing with clean, warm water. Buff the bronze with a soft, dry, clean cloth to achieve a new shine.

  6. Cover your bronze with a light coating of hot wax, heating it in a double boiler until liquid. Dilute the wax with a small amount of mineral spirits or lacquer thinner to create better adhesion (perhaps 1 tsp. to every 1 cup of wax). Brush on with a shoe polish brush or clean cloth, applying liberally. Allow the solvent, if present, to evaporate. Buff with a fresh cloth or clean brush to finish. This coating replaces the lacquer and prevents future oxidation, but should be periodically reapplied.