Fine & sterling silver naturally oxidize after it's been worn and stored.
Natural body chemistry, environment, and certain chemicals may oxidize or change the color of the metals.
The best way to prevent tarnishing is by caring for your jewelry properly and following these jewelry care tips.
Silver tarnishes faster in areas with high humidity and air pollution.
Additionally, contact with materials like cosmetics, hairspray, perfume, deodorant, body lotion, bleach, etc., can speed up the tarnishing process.
The silver jewelry may also become oxidized by reacting with acids in your skin, the moisture in perspiration, or by reacting with some other lotion or chemical on your skin.
Avoid exposure to chemicals such as chlorine, bleach, ammonia etc.
DO NOT ever use silver cleaner. This will remove the black axidation from the jewelry.