Pearls are organic gems composed of calcium carbonate.  They are more delicate than other gemstones; and  need to be cared for properly in order to maintain their natural luster.   Here are some helpful tips for keeping your pearls in good condition for years to come: 

Put on your pearls after applying your makeup and perfume.  Your pearls should be the last thing you put on as you dress.  You should also take off your pearls before you remove your makeup.

Wipe your pearls with a soft, lint-free cloth as soon as you take them off. The cloth can be dampened with water or it can be dry. If you use a damp cloth, allow pearls to air dry before putting them away. Do not hang pearls to dry. Lay them flat on a towel.

Dirty pearls can be cleaned with a mild soap and water solution. Never use solutions containing ammonia, bleach or other harsh detergents.

Do not put your pearls in an ultrasonic cleaner.

Store your pearls in a soft jewelry pouch, or in a special slot in your jewelry box. They may be scratched if other gemstones rub against them.

It's best not to store pearls in a hot environment.

You should not wear your pearl jewelry while exercising.   Perspiration can damage the surface of the pearls.

If you have a  pearl necklace that you wear often, it should be restrung once a year.