Pearls are considered the symbol of purity and chastity. But even symbols of purity get dirty from time to time. As you know pearls are produced when a mollusk secretes nacre to form a covering around a foreign body in its shell. Pearls are not as durable as gemstones produced by the heaving pressure beneath the earth's surface. Therefore special attention should be used when cleaning them.
Pearls should be the last thing that you put on and the first thing that you take off. Common personal products like cosmetics and perfume can severely damage pearls. They should be cleaned in warm soapy water periodically, gently scrubbing individually with a soft brush. A soft brush must be used so as not to scratch the surface of the pearl. Care must be taken to clean well around the drill hole, but do not dip the whole strand into the cleaning solution because water could get into the drill hole and cause the pearl to discolour. Also, if the silk thread becomes overly wet, the dampness can cause deterioration of the silk. All pearls should be knotted to prevent the pearls from rubbing against each other. If the strand ever becomes broken, only one pearl may become lost. Any dirt that has become caught around the knots should be removed with a toothpick very carefully. Pearls should be dried on a lint-free towel, laying them on an absorbent towel should hasten the drying process.
If the pearls are worn frequently, they should be re-strung on a regular basis and they should always be strung on silk. It may deteriorate faster, but it will not attract dirt or grime as quickly and it will not stretch. Pearls should never be stored with other jewelry. They should be stored in a moisture-free environment and should not be stored in a plastic bag. Pearls should always be wiped on a soft, lint-free cloth before being stored.
With care pearls can be worn for many years and even become a family heirloom.