I work at a jewelry store, a fairly upscale one. Most of my clientele come across as pretty classy people. Yet they have NO problem licking their rings to get them off...right before they place them in MY hand!

I've worked at 3 jewelry stores for a combined 12 years and this is not an uncommon occurrence. None of my employers have backed my suggestion that I lick them prior to returning them. Since I'm not good with subtlety, I don't know how to politely discourage this revolting behavior.

Suggestions?