My bronze item has changed color, what do I do?
You do not necessarily need to do anything.
Bronze goes through a natural oxidation process that starts immediately once exposed to the environment.
The metal undergoes a color change, at first darkening and finally gaining a light green or blue-green color called Verdigris (the statue of liberty is covered by it), forming a unique, protective patina on the metal.
The rate of patination is dependent upon the bronze's exposure to moisture, salt and acidity.
This color can stain your skin, all depending on the moisture and salts of the skin - but it's nothing dangerous and washes off.
What can be done is to paint the parts of the jewelry that are in contact with the skin with clear nail polish, which protects the skin.
While this darkened finish does add character to the bronze, some consider it unsightly, and would prefer their bronze to look clean and shiny
If you'd like, it is possible to restore the luster through simply letting the bronze soak in white vinegar and then carefully using a toothbrush on it.