Been useing Slimey Grimey for years and it works great. However the price of it has gotten ridiculous, like almost 30 bucks for the 1lb tub! I read the label and the prime ingrediant appears to be oxalic acid. This is also the main ingrediant in some wood deck cleaners which are at least half the money. Don't want to sound cheap but I dock & like to pull mine out every couple weeks and would rather put the extra money in the gas tank. Anyone else experimented with alternative cleaners?