Pour 1/2 gallon of hot water, 3 tablespoons of liquid dish soap, 1/2 cup of white vinegar, 1/2 cup of baking soda and 1 tablespoon of lemon juice into a plastic bucket. Stir the ingredients until they are well-incorporated, and pour the mixture into the reservoir of a plastic garden hose sprayer attachment. Set the sprayer attachment aside until the aluminum siding is prepped.
Pour 3/4 cup of powdered laundry detergent, 1/2 gallon of warm water and 1/4 cup of oxygen bleach into a plastic bucket. Stir the ingredients until the powdered detergent and oxygen bleach are completely dissolved. Pour the mixture into the plastic garden hose spray attachment.
Spray the aluminum siding with the garden hose and nozzle attachment to loosen any dirt, grime, chalky residue or mildew. Attach the plastic garden hose sprayer to the hose, and cover the aluminum siding with either homemade mixture using even, back-and-forth motions. Work the soapy mixture into the siding with a plastic scrub brush. Allow the mixture to remain for 10 to 15 minutes before rinsing it away with the garden hose, working from the roof to the bottom of the trailer. Allow the trailer to dry completely to determine if any spot-cleaning with either homemade cleaner is required.
Power-washing is an effective alternative to using either homemade cleaner, especially if you are planning to repaint the trailer. Slip on a pair of rubber gloves, and turn the power washer onto its lowest setting. Starting at the top, spray the trailer’s aluminum siding with the power washer. Work your way down the siding until the grime, dirt and chalky residue is completely eliminated. Power-washing removes the unwanted dirt, grime and chipping paint, making it a practical choice if a fresh coat of paint is required.