There are 3 main different types of pearls: simulated (man made), cultured freshwater and cultured (saltwater).
All strands of pearls should be treated carefully as they’re delicate. Simulated pearls can be destroyed by exposure to acetone (nail varnish remover). All pearls are extremely sensitive to perfumes, hair sprays, tans, moisturisers, etc. When using any of these products the pearls should not be exposed directly to them and the product should be completely dry before putting on the pearls.
Pearls are usually strung on silk string and you should avoid getting this wet at all costs as the silk will stretch and that will lead it to break very quickly. If you get your pearls wet, remove them immediately and wrap them as flatly as possible until you can lay them out on a towel and leave for at least 48 hours until the whole string is completely dry.
If you take care of your pearls you should very rarely ever have to clean your pearls. If however you do need to clean them use a soft cloth which is barely wet and has been thoroughly wrung out. Gently wipe the pearls with this cloth and then leave flay on a towel for at least 48 hours to dry. Do no use any soap or detergent.
Pearl earrings and rings are often glued to their setting so avoid any contact with water as this increases the likely hood of the glue perishing and the pearl falling off.