Whenever I purchase antique or vintage beads, that I know are not worth a monumental amount I place them in a small old bowl, add a little dish detergent and a small amount of ammonia and give them a few gentle swishes. You can see all of the dirt come off of them. Then rinse them well and place on an old dishtowel and pat dry and spread out on dry dishtowel and let them air dry. It really brigtens them up. Just be careful of precious stones.