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. 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! A wet Melamine sponge is also a great tool to remove tough stains without damaging the poly lumber. Keep away from direct heat sources.