I am a clean jewelry freak - here's my recipe -
Boil about 1/8 c (or less) of water in a glass measuring cup (microwave)
add an equal amount of ammonia (NOT while it's microwaving!)
add a few tsp of dishwashing soap...
Soak, then brush with an old toothbrush. Then I usually pour the cleaning concoction into whatever happens to be in the sink, needing washing!