I've been polishing bike ally for decades. Over the years I leaned different tricks and shortcuts to get a good finish. First you have to remove any war wounds, for this I use a nylon fibre wheel, not the same as a scotch brite wheel as it's harder and impregnated with ally oxide. These wheels are available in various sizes, widths and grits. I have a few ranging from 8"x2"and some 8"x1" for use on a bench grinder. You can also get small nylon fibre wheels for mounting in a drill. If you're into porting, these are brilliant, smoothing the bores in a matter of minutes and also polishing them if that's your bag, however, polished ports are not recommended for good gas flow. Next, you have to get the surface flat, if it's not already. Otherwise you end up with a surface looking like a good day at Bells Beach. For this I use a random orbital sander with decreasing grits. Once flat it's on to a sewn sisal wheel, then a sewn cloth wheel, then a loose cloth wheel then finishing off with Silvo and a soft rag. On the mops, black compound is for roughing and white for polishing, you can also use green, but the results are no better than white compound really. I've found Silvo is the best polish for maintaining the shine, much better than Brasso, Mothers, Autosol, ally wheel polish or any of the other commercially available aluminium polishes. Just rub it on with a soft cloth, allow it to dry, then polish it off with a soft cloth. Silvo is also great for restoring your glasses, indicator lenses and other plastic items and particularly good as a final polishing compound for painted surfaces.
