I inherited an antique buffet and its mirror is made of silver behind glass. I can see that someone used a harsh cleaner and washed away the silver on one corner, and I definitely don't want to repeat that mistake! I've avoided cleaning it, but every few months I wipe a damp rag over the mirror and quickly dry it off before the water seeps between the glass and the silver. Is this the best way to care for my fragile furniture?