Whether you have a set of pearls that has become worn and brown over the years, or you would like to lighten your pearls so that they are a delicate pink or a purer white, bleaching your pearls may be the answer. You must take care, though, since the bleaching process weakens the pearls and makes them more susceptible to crumbling and cracking. With the proper equipment, you can bleach your own pearls at home, just as many Chinese jewelry makers do in their professional warehouses.
Dilute your hydrogen peroxide. Start with a hydrogen peroxide solution that is two parts distilled water and one part hydrogen peroxide. The chemicals can weaken the pearls over time, so do not start out with a strong solution. You can always re-bleach pearls that do not lighten enough, but you cannot remake a pearl that has crumbled into dust.
Fill your glass jar about 2/3 full of the hydrogen peroxide solution. You need enough solution in the jar to completely cover the pearls. If you are bleaching a lot of pearls, you may need more than one jar. Start out slowly. Only bleach one set at a time, until you know what works best for you and your personal jewelry.
Seal the pearls in the jar with the hydrogen peroxide solution. The pearls should be completely covered with the liquid, and they should not be packed tightly in the jar. This will help the solution reach every part of each pearl.
Place the pearls underneath white florescent lights. You can use long-wave or short-wave UV lights for this step, if you prefer. Position the jar so that the light is directly hitting the pearls, not blocked by the lid. If you only have one light, rotate the jar daily so that all the pearls are exposed to the light.
Leave the pearls in the solution and the light for up to 7 days. Remove the pearls from the solution and decide if they are light enough for you. If they aren't, you can replace them in the solution for as long as three months, although stopping after 2 to 3 weeks is recommended. The longer the pearls remain in the solution, the less durable they become.