We recommend WOCA Exterior Cleaner for all decks because it can be washed away easily with a garden hose. The cleaning properties contained in Exterior Cleaner will not damage your lawn or surrounding plants. If furniture or other exterior wood surface is discolored or has clear signs of (black/green) growth, we recommend using the WOCA Exterior Deep Cleaner Spray because of its powerful grime cutting formula. It will effectively remove all growth and discoloration, but it is a harsh treatment and will also remove previous oil treatments. Be sure to re-oil with the Exterior Oil treatment used prior to using the Exterior Deep Cleaner Spray. For less affected surfaces, use WOCA Exterior Cleaner.