I’ve been using this cream for a couple of years to get a mirror polish on all the vintage bicycles I collect. Before discovering it on a listserv about classic bikes, I tried various buffing and polishing compounds (usually automotive) and Nev’r Dull, which worked fine but requires a lot of effort. Simichrome seems to work magically, with very little elbow grease needed to dissolve/remove surface stains and oxidation (the main ingredient is aluminum oxide). The results are astounding. I’ve used it primarily on aluminum, and a few chrome pieces. In my experience it works best on aluminum. Recently, I revived a set of oxidized aluminum cranks in under an hour all told — sanding and steel wool to remove scratches and then less than 10 minutes (and minimal effort) polishing with the Simichrome. For aluminum parts that don’t need scratches sanded out it takes about 30 seconds to watch a small section go from dull, oxidized metal to mirror finish (that’s not hyperbole). Of course it depends a bit on the finish of the underlying metal, how big and complicated the part is and so on. I’ve tested it on brass, and though it wasn’t as easy on that as it was the aluminum, Simichrome was still much quicker than anything I’d used before (Turtle Wax, buffing compound, Ajax, steel wool).