Aluminum siding can be cleaned by scrubbing the surface with natural cleaning detergent and rinsing the area with a pressure sprayer set on low. Pressurized water helps to dislodge ground-in dirt and debris that often occurs with prolonged exposure to external elements.
If low-pressure water does not get the job done, a higher level of pressure can be used. It is important to test the pressure levels prior to spraying to prevent damage such as pitting. Pressure cleaning vinyl siding once in the fall and again in the spring can help to slow down deterioration.
Oxidation is a common issue that causes a chalk-like film to develop on aluminum siding. Mild oxidation can usually be treated by applying a non-acid oxidation removal solution directly to the siding and following this up by polishing the affected areas with a soft cloth. Heavy levels of oxidation can be treated by power buffing the affected areas with acid-based oxidation treatment solutions. Acid-based solutions can cause additional pitting in the aluminum, so it is important to spot check the areas during the cleaning process. If pitting or paint damage occurs, the areas can be smoothed out with sandpaper, a soft cloth or a buffing machine.