There is a good chance your jewelry includes sterling silver, which oxidizes and tarnishes as a natural result of the moisture in the air. There are two ways to insure that your jewelry will always look its best. First, minimize as much tarnishing as possible. Some jewelry boxes have a lining designed to do just that. Another method is to store sterling silver in an air tight zip-lock bag. You can also place a piece of chalk in with the jewelry.
It absorbs moisture.

The second way to care for your jewelry is to clean it regularly with an anti-tarnish silver polish. We use Wright's Silver Polish, but anything comparable would be fine. It is found in the grocery store and easy to use. Simply follow the directions on the bottle. The polish does not harm stones, pearls or crystals on jewelry. We have found that the polish is much better than cream, which is too thick and difficult to rinse out of some of the fine designs on the silver. We also don't recommend any of the liquid dipping solutions, which can dull imported silver and adversely affect pearls.

For a quick clean up of Austrian crystals, a light touch of glass cleaner works well.