What’s the best way to clean my aluminum siding?
Aluminum with a faded, weathered look needs to be cleaned with a strong detergent solution, but you might want to test this solution in an inconspicuous spot on your house first. Washing may result in a color that is not uniform after it dries. If the color in your test area is consistent, it’s safe to clean the rest of the siding this way. To make a detergent solution, combine 1/3 cup laundry detergent, 2/3 cup trisodium phosphate (TSP), 1 quart household bleach (5 percent), and 3 quarts water. Avoid any abrasive cleaners; these will damage the finish. Clean your siding once a year with a strong spray of water from a hose. Use the detergent solution when the siding begins to look old and weathered.