Not sure whether anyone here has tried it. But acetone in the gas tank is a pretty hot topic in many car (and personal finance!) forums. There's a whole Wiki page on it (http://www.peswiki.com/index.php/Directory:Acetone) and I felt convinced enough to give it a go. Basically, you need to buy laboratory grade acetone for best results, but I've read that the Sally Beauty stuff works well too. As for concentration, that takes a bit of experiment. Basically, you put in between 1 - 4 oz per 10 gallons of fuel - treat it like an additive.

For the record, I drive a Nissan Sentra B13. I've tried a 3 oz concentration - mileage got worse. I then went down to 2.5 oz, 2 oz and 1.5 oz concentrations - didn't work. I'm down to 1 oz and am starting to notice a slight improvement. Will post updates on this later.

My testing is not entirely scientific, and the higher concentrations were applied when my oxygen sensor wasn't working too well, so that could have been a factor. But I've since changed the sensor, so maybe I should retry a higher concentration.

If anyone has tried this first hand, I'd welcome any comments.