Great Exterior Cleaner for all surfaces- Wood, Concrete, Painted Surfaces (to Clean prior to repainting- Not A Stripper!), Canvas, Boats, etc.  Removes dirt, weathered wood fibre, mold, algae and most prior penetrating oil based wood sealers, leaving a Clean, Pourous Surface (for Sealing or Staining, if desired).  Great product size for repeat users like Contractors (just add two cups per gallon of warm water, mix, apply, brush and rinse or lightly pressure wash).  Does not contain Bleach so it is personally safer to use than products with Bleach (Chlorine).  Also, since Bleach removes Color and degrades the integrity of Wood Fiber and man made surfaces like Fabrics and Paints, Deck Cleaner results in cleaning, not color or substrate deterioration.