Lotions, cosmetics, hair spray and hair products, and perfumes are “enemies” of silver and brass and will accelerate tarnishing, so it is recommended to always put jewelry on after you are done applying these products. Contact with household chemicals, perspiration, rubber, chlorinated water, or any substances which contain sulfur will also cause corrosion and tarnish — so it’s a good idea to remove silver jewelry when doing household chores. Direct sunlight also causes silver to tarnish, so be sure to take off your silver jewelry before you go swimming and sunbathing.
Because moisture and sunlight both promote tarnish, the best place for your jewelry is out of direct sunlight and away from excessive humidity in an airtight bag or container. If available, place a moisture absorbing product inside your jewelry box. White chalk, charcoal or silica gel will absorb the moisture which causes tarnish.
Brass Jewelry: Brass is a copper alloy, therefore the metal will naturally patina and darken with age. Water and heat hasten the formation of patina on the metal. Showering, swimming or exercising in your piece will almost immediately cause discoloration. Slight discoloration of the skin may happen from time to time. All skin types are different so variance of patina's will depend on the skin type. To return pieces to their original finish, buff with a polishing cloth and keep stored in an airtight bags.
Sterling Silver Jewelry: When silver is not worn regularly, it will darken and tarnish. You can avoid tarnish by wearing your jewelry often. The oils in your skin will “clean” the silver and keep it looking shiny. To return pieces to their original finish, buff with a polishing cloth and keep stored in an airtight bags.
Gold-fill Jewelry: Gold-fill jewelry will require an occasional wipe with a polishing cloth to maintain it's vibrance. Over time, wear and tear might burnish your piece, leaving it shiny or a different finish than when it arrived. If you'd like to return the piece to it's original finish, simply use a gentle polishing cloth or wash with cool water and baking soda.
Stone Jewelry: With all jewelry, do not use baking soda or chemicals of any sort on stones. Simply a toothbrush and mild soap will do.