Aluminium is silver-coloured metal that is used on storm windows and other outdoor furnishing because of its resistance to weather and salt air. However, aluminium reacts easily with oxygen in the air and the outer surface can become oxidised with a dull grey coating. This is called oxidation, or combining chemically with oxygen. You can't always stop aluminium from oxidising, but there are some things you can do to remove the signs of oxidation from your aluminium storm windows.
Clean the dirt from the aluminium on your storm window by using a rag or sponge with mild detergent and water. Dry the aluminium with an old towel.
Combine a no-scratch cleanser like Bon Ami with a small amount of water to make a thin paste. Take a sponge and wet down the surface of the aluminium. Use a scrubbing pad, such as a Scotch Brite pad, to work the paste into the surface of the aluminium around the window. Scrub gently to remove the oxidation. Rinse the aluminium with the sponge and clean water. Don't let the cleanser dry on the aluminium or it will be difficult to remove.
Wet the aluminium and scrub it again with a very fine steel wool pad to remove any additional oxidation. Dry the aluminium with an old towel.
Use a clean rag to coat the aluminium around the window with a thin layer of automobile wax to try to prevent further oxidation.