How to Clean Dirty Trex Decking

Sweep the deck, moving in a single direction with a push broom to remove any loose dirt and debris.

Wash any remaining light dirt deposits from the deck surface with a hose. Spray off the deck in rows, moving with a back and forth motion in the same direction you swept the deck in order to avoid spreading the dirt further over already cleared sections.

Wash embossed areas with a warm soap and water mixture and a soft bristled scrub brush. Scrub lightly over the embossed patterns with the brush in a circular pattern to loosed the dirt within the pattern details. Use the soap and scrub brush to clear away any mold or milder present on the decking as well. Rinse the soap off with water from the hose.

Apply a deck brightener containing oxalic acid to the still wet deck surface using a mop and allow it to sit on the decking for up to five minutes to penetrate ingrained dirt, scale deposits, tannin and rust stains.

Rinse the deck brightener off the deck surface with the hose, clearing the surface completely.

Clean the railing with a pressure washer set to 1,500 psi. Hold the washer 4 inches from the railing surface then work your way down the rails with the spray, removing all dirt buildup. Allow the deck to dry completely after cleaning.