Recommended Cleaning and UV treatment times: Every 4-6 weeks or in hotter weather or heavy use sooner. Clean soiled covers with a mild soap like DAWN ( NOT DETERGENTS). Remove covers If you wish from rails ( NOT REQUIRED ) WASH BY HAND (NOT MACHINE WASHABLE) wash in a warm water solution, scrubbing soiled areas. Rinse in cold clean water and ring excess water by hand. Hang covers up to drip dry ( COVERS ARE NOT DRYER SAFE). Allow to dry completely. Do not apply Harsh Solvent type cleaners or additives like Scotch Guard products to the covers. Re-apply a new coat of 303 Aerospace fabric protectant to entire outside cover area. Allow to dry completely. Wet covers again re-install covers on rails. Disclaimer: Pool chemicals, detergents, chlorine products, suntan lotions, natural body oils and Ultraviolet light may fad, soil and degrade materials or create stains not removable.