well I sandblasted... that turned out to be a mistake. so for sandpaper I used 180 220 320 400 600 800 then 1000. If I hadn't sandblasted I could have started with 600 probably and saved myself a ton of time. Then I used mothers aluminum and mag polish to finish it off. I polished part of my pipe and it was a constant battle to keep the water spots off. It was not a lot of work though. just rub it down with polish for 30 seconds and its back to perfect but you have to do it every time you ride. There may be some sort of wax or something that will keep it down but I don't know what it is.