Well-polished aluminium can look like chrome but it takes time and patience to get the glossy mirror finish. You will need to work methodically to get this shiny finish. The main thing to keep in mind when you are polishing aluminium is that the smoother you get the aluminium, the more mirror-like it will be when you are finished.
Wash the aluminium using a liquid dish detergent. This will remove any debris, which makes polishing the aluminium easier. Allow it to dry completely.
Check the aluminium for anodising. This is a substance that makes aluminium look brushed. Use regular oven cleaner to remove the anodising. Spray the oven cleaner on the aluminium and leave it alone for 10 minutes (less time if the aluminium is thin). Wipe the anodised areas with the towel using a circular swirling motion to remove the oven cleaner. When the anodising is removed, the area will look very bad. This is normal. Rinse the aluminium with clean water, then dry the area.
Clean the aluminium with paint thinner. This prepares the aluminium for sanding. You should pour paint thinner onto a clean towel and wipe the aluminium in a small circular pattern. Rinse the aluminium off with clean water.
Sand the aluminium using 320 grit sand paper. Wet the sand paper and the aluminium and begin sanding. This is called wet sanding. Take your time and make sure that you sand the entire surface.
Continue sanding using the same method with sand paper of higher grit. For example, use 400 grit, then 600 grit followed by 800 grit, then 1200 grit and finally 2000 grit. With each new grit, you should remove all the marks from the previous grit. By the time you get to the 2000 grit, the aluminium will be very smooth.
Buff the aluminium using a buffing pad and brown cutting compound. Use circular motions. After you buff using the brown cutting compound, rebuff using a clean buffing pad and rouge cutting compound.
Wipe the aluminium off with a flannel or chamois cloth. This will remove fingerprints and smudges.
Wear gloves, a respirator and protective eye goggles or glasses when you polish aluminium. Use an orbital sander to sand and buff if you are working with a large piece of aluminium.