Use one cup of water and a few drops of shampoo. Any type of shampoo is fine to use. Pour the shampoo and water into a bowl and stir using a spoon or other utensil.. Don’t dip the pearls directly into the mixture. Instead, use a small and clean makeup brush. Dip the makeup brush into the mixture. Go over each pearl with the makeup brush. Make sure to clean every part of the pearl, even the part near the setting. Use a damp cloth that has been wrung dry. Gently rub the pearls with the damp cloth to rinse the mixture off.  Allow the pearls to dry on the soft, dry cloth they were originally laid out on. Pearls are fragile and easily damaged by harsh cleaning methods. Always put on your pearl jewelry after applying makeup and aerosol products. Clean immediately after perspiring and being in smoky environments.

Summary:
Create a mixture. Go over the pearls with a makeup brush. Rinse the pearls with a damp cloth. Practice preventative cleaning measures.