I have a 12 x 20 deck and an old but healthy pet cat who likes to munch grass underneath it. This deck is pressure-treated, new in 2003, but now it looks like Hell (we're in NE PA, in the Poconos, where the living ain't easy). We're slated for a string of clear days, so I want to get the deck cleaning and painting out of the way. A Google search of "non-toxic deck cleaners" turned up very old hits from 10, 11 years ago, so--
What chain store sells the cheapest, non-toxic deck cleaner?