If your wood deck has a weathered solid stain, or an unweathered semi-transparent stain use a deck stain stripper to remove these products.
If the semi-transparent stain is faded and graying, then an oxygenated bleach wood cleaner will work like DEFY Wood Brightener.
Watch this video to find out whether you should use a stain stripper or wood cleaner to prepare your deck for stain:
