Poly lumber is easy to clean and maintain. Dust with a soft cloth or soft bristle brush, and tend to spills and stains with a mild soap and water. If you encounter a stain that is hard to remove, use a wet Melamine sponge to scrub it without damaging the poly. We do not recommend power-washing your poly lumber furniture, but if you do, you must keep the power-washer at least 12 inches from the surface of the furniture and do not use a stronger setting than 1500 PSI. No waterproofing, no staining, and no painting is ever required!