If you have an antique bronze object such as a statue or piece of jewellery, you should think very carefully before cleaning off the surface patina. For many objects, part of the value stems from the aura of history and age that a patina creates, including the characteristically green patina of verdigris. All patinas come from the reaction of metals to the environment and in the case of bronze it comes mostly from the chemical reaction of the copper element of the alloy, which also most commonly includes tin and sometimes zinc.
Dust your object with a dry, lint-free cloth. If the object has nooks and crannies that are difficult to access, use a small paint brush.
Rub the surface of the object gently with white spirit to remove grease or dirt. Use a cotton bud for a small object and a cloth for a large object.
Scrape of the loose green dust that can collect around patches of verdigris with a sharpened bamboo skewer. Wipe the area exposed by the removal of the verdigris with white spirit.
Get the advice of an expert before working on your antique bronze object to ensure that you will not decrease its value by cleaning it.
Verdigris contains chemicals that can be hazardous, so wash your hands thoroughly after working on your object.