Pearls are an organic soft material requiring special care. Pearls react well to natural skin oils so it is good to wear pearls regularly to maintain their lustre. Do not expose pearls to any household or industrial chemical cleaning agents, they are vulnerable to acids and ammonia, and these chemicals will dramatically affect their lustre and disintegrate them over time. Avoid exposing pearls to excessive heat as they can crack if the atmosphere is very dry. If pearls come into contact with coloured dyes e.g. a pearl necklace worn on a red jumper then they can absorb some of the dye colour.