Soak for 20 minutes in a solution of one cup warm water and 1/4 cup ammonia. Then gently scrub with a soft-bristle toothbrush, getting into the small areas between the diamond and the setting. Rinse with warm water, and lay on a tissue to dry. If your diamonds are set in platinum, this method will also clean the setting.
Care Tip: Avoid contact with chlorinated pools or household cleaning products containing chlorine bleach, which may discolor the mounting.