If there are other gemstones on your ring, it is better to use a soap and water solution or other mild detergents that do not contain ammonia. Below are some ideas on how to clean diamond engagement ring using an ammonia solution.  
  • Fill a bowl with an equal proportion of cold water and ammonia. Mix it well and leave your diamond ring in the solution for about half an hour.
  • In the meantime, fill another glass bowl with hot water in comparatively greater proportion, mild liquid detergent, and a splash of ammonia, in order to make a scrubbing solution.
  • After 30 minutes, take the ring out of the ammonia solution and clean the ring using the scrubbing solution you made. Use a soft-bristled brush to clean the ring efficiently. Take care to rub the ring gently and circular motion so that you do not damage the setting.
  • After scrubbing, keep your ring under tap water and rinse it thoroughly until every trace of ammonia is washed off. After rinsing, either clean the ring using a lint-free cloth or just air dry it.