Lighter Fluid would be a milder version of Goof-Off.
It will haze the finish, & you should be able to restore it's finish with a dab of oil?
It must not sound all that well if you spend considerable time looking at it, instead of enjoying it's sound? Why not just sell it, & find another more visually pleasing unit? Prior to reducing it's physical condition / resale value?
Or see if another finish option Face Plate is available from the manufacturer, & then sell this units Face Plate in a non-marred state? Good Luck!
It will haze the finish, & you should be able to restore it's finish with a dab of oil?
It must not sound all that well if you spend considerable time looking at it, instead of enjoying it's sound? Why not just sell it, & find another more visually pleasing unit? Prior to reducing it's physical condition / resale value?
Or see if another finish option Face Plate is available from the manufacturer, & then sell this units Face Plate in a non-marred state? Good Luck!