Tarnishing of fine metals is a natural process caused by oxidation, and does not damage silver, copper, or gold. Tarnish can easily be removed by rubbing the piece gently with a soft, treated polishing cloth. Polishing cloths may be purchased at local jewelry stores and department stores.
If you want to "brighten up" your silver, it's easy and you don't have to use chemicals like silver polish. Just place your silver in a non-coated aluminum pan with a couple spoonfuls of baking soda and pour boiling water into the pan. Make sure you don't use a favorite pan as the oxidation from the silver will be transferred to the aluminum pan. Or try something they do in Thailand — soak your beads in lemon or lime juice — diluted with a little water. Just be sure to thoroughly dry your jewelry after exposing it to water.
Avoid chlorinated water, salt water, abrasives and sterling silver dips to be on the safe side. Moisture, especially in an enclosed storage space, will tarnish sterling silver, loosen jeweler's cement (used for stone setting) and weaken springs and clasps. Also water of any sort will rob Ethiopian opals of their color. Pearls and opals draw moisture from the air, so storing your opal or pearl jewelry in a dry area, such as a safe deposit box, can sometimes do more harm than good.
As for the care of your pearls, they require a bit of TLC to keep them looking pristine. Acidic elements such as perfume and even perspiration can dull a pearl's lustre, so never spray scent directly onto them and wipe the pearls before putting them away. Pearl jewlery should always be stored separately from gemstones to ensure the harder stones do not scratch their surface. Try putting your pearls into a cloth or silk bag before placing them in your jewlery box. With pearl necklaces, it is a good idea to take them to a jeweler every 5 years to see if they need re-stringing.
Most colored gems can be cleaned with warm water, mild dish soap (no detergents) and a soft brush. A pulsed-water dental cleaning appliance and a soft, lint-free cloth can also be used. Be sure to rinse your jewelry in a glass of water to remove cleaning solutions since you risk losing loose stones – or even an entire piece of jewelry - if you rinse directly in the sink.
Fine jewelry should be removed before diving into a chlorinated swimming pool or before using household cleaners. Many of these cleaners contain ammonia, which can be too harsh for delicate gems or vintage jewelry. Chlorine bleach, another common household solvent, can pit or damage gold alloys.