Paint Removal?

Maybe you can take a q-tip and put a little paint remover on a part of the preamp you can't see and see what happens. I'm sure other people will have better idea's

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!

Thanks guys for the responses. Much appreciated.

Audio,

The unit sounds great (AE-3 DJH) and it's all of a day old! Vast improvement over my previous pre-amp (a Linn Majik) and looking forward to the DJH hitting its stride. Will go into more detail when I update my system page.

Best,

Albert gave you excellent solvents to use. Any of them should only be used in a well ventilated area away from ignition sources as they are all very volatile and highly flammable.