Drillium Dude had a series about doing the drillium work and it included a thread about filing and sanding the imperfections on tome worn and scraped aluminum parts. Here is a link for the third in the series:
http://www.bikeforums.net/classic-vi...g-sanding.html
I have used this as a reference for bringing back various alloy components to a respectable appearance. DD has some serious skills for the detail work that makes bikes pop and look highly respectable. I used his method on a few pairs of Campagnolo Victory, and Super Record levers this spring. I was pleased with the smooth feel of the repairs to some serious asphalt scrapes on them.
To finish polish them, I used Dawes Industries, Diamond Brite aluminum polish, and soft clean cotton cloths, and I took them over a standard polishing wheel, on a bench grinder, to get the surface clear of all dust and debris from the filing and sanding before I began. Taking my time and not getting anxious about what was happening was a big part, use a light pressure with the polishing wheel and keep the surface cleared as you go.
Good luck with your work, as Lazyass said, it can get addictive.
Bill