There are some gems that should never be cleaned with anything containing ammonia, chemicals or harsh solvents as the gem can become discolored, pitted or damaged.
If in doubt, simply clean the piece by wiping it down well with a clean cloth.
1 cup warm water
1 TBS ammonia
small squirt of Ivory dish detergent
- Mix ingredients then soak pieces, clean with a soft jewelry brush. Dry fully before storing away.
Important: Here’s a gem care chart to review  before using an ammonia based cleaner.
Another option: Just a mild soap and water solution will safely clean many different types of jewelry in most cases. Please review the gem care chart before doing so.
- For sterling silver, I’ve seen recommendations to use baking soda or toothpaste–but I’ve been told it’s a bad idea since that method can cause fine scratches that only a professional will be able to remove. And with great difficulty at that. Only silver cleaning cloths and polishes should be used.
- Have a jeweler inspect your rings and other pieces annually to check for loose stones and tighten clasps where necessary.
- If you’re looking for information on how to maintain & repair vintage and costume pieces, here’s a page bursting with info: Sparklz.com 
- Chlorine can damage gold, platinum and some types of gems. Don’t wear valuables in hot tubs, swimming pools or wear when cleaning with bleach.