One of the things I do for a living is polishing things. I can tell you that although you can polish that out, it is very labor intensive work and you have to be very careful about rounding the edges off. For me, I`d chuck it in the lathe and take a "hard" felt wheel to it to remove the most of it without taking the corners down, or rounding them off, then I would final polish with a soft muslin wheel.
I can also tell you that by the time you get it right (if nothing goes wrong: spins off the drill or chuck or flies through the room breaking something on the way, LOL) ), buying a new polished one will seem like it was the easiest solution.
Just saying.