I use an electric fingernail buffer for fixing all my discs, feel a little gay at times when I'm doing it but the results are worth it. 7 different heads for the buffer, from a cloth felty thing too a rough metal file type dealie.
On the sanding note, I sanded the bottom of one of my star wraiths earlier this year and found I was able to hyzer flip it into a sweet turn with my sidearm. obviously I was a little overzealous with the sanding, use extremely fine grained sand paper if you are using it on large areas. as for small dings, I think its best to use something that will only hit the area you want to fix (like an electric fingernail buffer...ask your girlfriend, just don't tell her why you need it lol).
