Is there a way to take off old permanent marker from a coin/medallion?

As a kid of 8 or 9 years my mom worked at The University of Minnesota during the big renewal project in 1986 on the UMN's 75th anniversary. She received, for her part in the process, a br (or some other metal that oxidizes with air) medallion to commemorate the completion. She wasn't too keen on awards or medals as her work ethic didn't include winning awards, she figured the job well done was award by itself. Anyway, she essentially gave me the medallion to "play with" and subsequently this future coin collector who didn't know any better marked it all up with permanent marker to make it a cool looking black medallion. Over the years (starting with that first day of total marker coverage) the marker has worn off, but in some deep portions of it the marker still exists and has made an unsightly dull grayish oxidization appear. Now, I can't remember if the medallion was supposed to have an antiquing look to it or not (I don't think so) but that marker is proving a ***** to take off. I've done the vinegar and salt thing to shine it up, and I've tried 99% alcohol for cleaning electronics to dissolve it off (since I can't reach it by soft brush or mild eraser). No go. What next? Is the 99% alcohol telling me the darker portions "are not marker you dumb dumb ignorant man"? lol ;)