To clean yellowed cultured pearls, gently immerse and swirl the pearls in either a jewelry cleaner specifically made for use with pearls or warm water and a mild detergent. Rinse the pearls carefully, and lay them to dry on a soft, clean cloth. Allow them to dry completely before storing or wearing the pearls. Due to the delicate nature of pearls, many jewelers offer pearl cleaning specialty services.
When cleaning cultured pearls at home, never expose pearls to harsh detergents such as dish soap or laundry soap, powdered cleansers, bleaches, ammonia-based cleaners or backing soda. Do not rub the outer surface of the pearl, known as the nacre, which gives the pearl its sheen. Do not use an ultrasonic cleaner or steam-clean the pearls. Never scrub a pearl’s surface with a scouring pad, toothbrush or other abrasive material.
To restore the sheen of pearls, wear cleaned and thoroughly dried pearls for a few hours, transferring body oils to the pearl’s surface. A tip is to wash pearls in salty water, mimicking their original oceanic environment. To refresh the appearance of pearl jewelry, have the pearls restrung once a year. To restore shine, use only chamois leather to gently buff the surface of the pearls.