Wash the bronze piece with liquid soap and water. Use a soft-bristled brush to clean into recessed areas. If the bronze item still has quite a bit of dirt on it, dip it into melted paraffin wax and allow the wax to harden. Peel the wax away and the dirt will stick to the wax.
Add a few tablespoons of fish tank cleaning solution into a gallon of distilled water. Fish tank cleaning solution is a pre-mixed cleaning solution that is used to clean mineral deposits and other soil from fish tanks.
Soak the bronze item in the cleaning solution and distilled water for up to three days.
Rinse the bronze piece with distilled water. Mix a fresh batch of fish tank cleaning solution and distilled water and place the bronze item back into the cleaning solution for up to three days.
Remove the item from the fish tank cleaning solution and distilled water and soak the bronze piece in distilled water for up to three days. Repeat the process until all of the pitting is removed.