Quoted from Champ1973:My 1969 Chicago Coin has brown discolor and so far the only thing that removes them without ruining the paint are alcohol pads. It would take me months to do it this way. My 1976 Zaccaria had the same stains. Anyone know what it is, and the easiest way to clean it off? Thanks.
I have found this to be nicotine in the past. A Magic Eraser has worked great for me. Just do a small section in an unseen part of the cabinet before you go to town.