Brilliant Cut Grinder

[Bakin4Life]

I imagine you could do a halfway decent job with something like a dremel, the correct polishing attachment, and the right polish. There's more to it than that (like maybe repeating all the steps several times with smoother & smoother material, etc, etc.) That's how car finishes are done, anyway, which is what came to my mind.

(on edit / forgot): And if you were to do something irreversible, it's only on the inside

You'll need to do some research. Same as me, if I were to try. Keep us posted!