Small amount of liquid dishwashing detergent
1 teaspoon ammonia
Mix detergent with ammonia. Let the jewelry soak in this solution for about five minutes. Gently scrub with an old toothbrush, cleaning inside the setting and under the stones. Rinse well. Put the ring in a little alcohol; buff with a soft cloth.
Use only on hard stones and diamonds. DO NOT USE on soft stones such as pearls or opals.