How do you keep a decanter stopper from sticking? [View all]

I bought an old tantalus at the thrift store today. It consists of an open metal carrying apparatus (with lock and key) and 3 very nice glass decanters for gin, scotch and rye. One of the stoppers was stuck and after a half hour of messing around with it I got it unstuck and could remove it from the bottle. I washed them all and they're now air drying on a towel, but I'm wondering if I should oil the stoppers or do something to prevent them from sticking again. Any suggestions?