I have done many things to clean mine, but have never gone all the way and made it "sparkle". I will be doing that in the next week or two though. I use a collection of nylon brushes in various sizes, as well as wire brushes. I use Mean Green (carefully, and in certain areas and NEVER leaving it on very long), plain ol' water in a spray bottle, brake cleaner, etc.
It takes a lot of elbow grease and takes a while to do, however, it brings great results and is perfectly safe if done correctly. To knock the dust off this week, I just sprayed it down with the hose with light pressure. This was a good start so that I can really attack the "heavy" stuff by hand.