Nice looking machine
From the look of those pictures, if it were mine, I wouldn't worry about a few "battle scars". I regard them as badges of honor. But if you're determined to make it 'perfect', then you'll need lots of sandpaper (in multiple grades) and elbow grease. You'll want to use wet/dry sandpaper like they use for automotive body work. Keep a dish of water nearby and keep the sandpaper moist.
Start with something fairly coarse (120-180) and sand perpendicular to the scratch until you can't see it anymore. Then switch to a slightly finer sandpaper and repeat the process, sanding perpendicular to the way you sanded the first time. Keep repeating this process with ever finer grades of sandpaper until you get up to 1600 or 2000, by which time the metal will be shiny again. Finish it off with some Mother's metal polish on a soft cloth and then put on some good car wax to keep the metal from oxidizing.
