The creatures have been conducting some experiments recently and have discovered that using a hose blasting water into the tank (which knocks off all the rust), then soaking overnight in vinegar, then soaking overnight in gas, then flushing works beautifully. We had some real horrorshow tanks, and they are beauties now. We're trying cola on another tank as I write. I'm sure someone will be aghast, but this is creature science at work, so back off. Bear in mind these are actual experiments we are testing here, not second hand news. The long term effects? hmm, who knows.