I love pearls. Every shape, color and size. There are so many different kinds of pearls to choose from. There is one thing they all have in common, they are all natural. A cultured pearl may have a little help getting started, but it still grows in a natural environment. Pearls are very porous and this is an issue when it comes to care.
The do's of care are very simple. Just be gentle. The nacre (outside layer of a pearl) is very fragile. Therefore, be sure not to just throw your pearl in a drawer with your diamond ring. Chances are, the diamond will scratch the pearl. Clean your pearls with a lint free cloth. If they are really dirty dish soap and warm water is the best. Once you have rinsed them off lay them flat on a towel to completely dry. The string used for pearls is silk. Be careful not to touch the string while its wet as it gets dirty very easily. It is recommended that you have your pearls re-strung once a year if you wear them often. This is due to the silk weakening. The funny thing about pearls, they are formed in a wet environment so they need the natural moisture in the air, but they really don't need to be immersed in water on a regular basis. That being said, be careful not to store your pearls in an airtight box this will prohibit them from drawing moisture from the air, and will increase the chance of discoloration.
The don'ts are simple; don't swim in a swimming pool or hot tub with your pearls on. Salt water is not the end of the world for pearls but as I said earlier, the string may not look all that great when you get out of the water. Finally the don't most of us don't think about. Make the pearls the last thing you put on when getting ready. Hair spray, makeup and perfumes/colognes are not friendly to pearls.