Is your wood deck stained or discolored? Several products are available
for dealing with these stains and related problems. Commercially-available
powder or liquid-concentrates have a base of non-chlorine bleach or oxalic
acid; a detergent may be part of the formula. Bleach-based products eliminate
mildew, acid-based materials handle graying and stains. Some products may
darken woods such as redwood and cedar, so be sure to test any material
in an inconspicuous place.
Always wear rubber gloves, goggles, and old clothes when working with these
chemicals and follow the directions explicitly. Caution: Never mix detergent
containing ammonia with household bleach; the resulting fumes can be highly
toxic.
--Don Vandervort