Storing them with a small container of water in an enclosed area, such as a vault or safe, will help keep the lustre. As the pearls are kept moist, they will not dull.
We have always found that to work best.
Oddly enough, a little olive oil, wiped very, VERY lightly and gently over the pearls can help restore some of the lustre as well.
In such instances where pearls are losing their glow, it is better to allow a jeweller to deal with them.
--Previous Message-- : I have a question I have been wondering about : for some time. How is the luster of pearls : maintained in a tiara setting? Pearls are : delicate things. As far as I am informed : they should be worn next to the skin : regularly to keep their luster. Queen : Margrethe II informed us in the film about : jewels that her mother wore an ancient pearl : necklace under her clothes for months in : order to restore its luster. How do the : pearls in tiaras keep it ? :