About Deck and Fence Brightener Instantly brighten decks and other exterior wood with Wolman Deck & Fence Brightener Wood Cleaner & Coating Prep. This 100%-biodegradable formula applies easily, clings to vertical surfaces and lifts dirt in just 10 minutes. Chlorine free, 100% biodegradable – will not harm plant life, damage wood lignin or leave a bleached-out look. Restores UV-grayed, dirty, mildew-stained wood surface to a bright, like-new appearance. Fast and easy to use - mix with water in less than 1 minute, does the job in 10 minutes!