On a warm dry day stand the cover on end and allow the cover to drain fully of any water that may have accumulated. Using warm soapy water and a clean soft cloth, wipe the entire cover down. Rinse the cover of all soap and allow to fully dry. Treat your cover with a conditioner that includes UV protection. There are several on the market made specifically for spa cover use and are highly recommended. Products such as Armour All, Turtle Wax, and petroleum-based cleaners will cause the cover to dry dramatically and crack.