It depends what kind of rock it is. Polishing can be done to virtually any rock type. Vinegar won't always bubble much if the calcium levels are very low, in which case there isn't likely enough to alter water chemistry anyway. I like to use CLR to test rocks, it's a stronger acid and is completely water soluble, so it's as easy to rinse off as vinegar is. I rinse and scrub any new rock no matter where I get it, just to be safe.