That dude is bs'ing with the acetone. In fact, I don't even know if he did a test. He has a 2000-2003 model Acura TL. The city MPG on that is 17 and the highway is 27. That's the standard on sticker. I only know this shit because my dad has had 3 models of the TL. That dude's start and finish MPG is based on where he was driving. As for the 34 MPG, he's either lying or he was driving in Iowa for hours on cruise control at 50 MPH.
Keeping your tires inflated at the proper PI, keeping a clean filter, staying up to date on oil changes, windows up, using cruise control whenever possible, and less braking are all things I commonly practice to make mileage better.