Back when I worked at a jewelry store, a panicked bride came running to me, sobbing. Her mother had given her a set of pearls to wear on her wedding day that had been handed down through generations of women in her family, all of whom wore these special pearls at their weddings. Since the necklace was many decades old, the bride decided to give the pearls a bath -- following the instructions on her jewelry cleaner, she proceeded to ruin her wedding necklace.
Pearls are one of the most fragile gemstones out there. Real pearls are especially delicate, but even simulated ones won't always hold up to standard cleaning methods, as cleansers can cause the dye to flake off or discolor. Whether your pearls are natural or faux, you need to be careful when you clean them, just as you are careful when you wear and store them.
To clean pearls, do not use standard ammonia-based cleansers. Instead, fix a bowl of warm, soapy water, and get an old, soft toothbrush to very gently scrub the pearls. Pat them dry with a soft cloth or towel when you are finished, and they're ready to go. If this doesn't do the trick, take them to a jeweler for a better wash.
If you do accidentally wash the dye right off your faux pearls, it's not easy to re-dye them, because most paints won't stick to the surface of the beads. The one thing that we've learned actually works is shoe dye -- but please don't try this on natural pearls!
Courtesy - wal-land