I have done it. Truck is a 90 chevy 1/2 ton with a 350 and TBI. HEard about it and thought what the hell.
Never noticed ANY MPG gains with 4oz per 10 gallons, though that may have been too much. It did seem ot gain some HP, but that is subjective. I need to experiement more to get a better idea of what works and what don't, perhaps I have too much in there.
Basic premise is that 2-4oz per 10 gallons will increase milage by 10-30%, but too high a concentration and milage will plummet significantly. Supposedly the engine will run cleaner, and produce less emmissions, and beautiful women will come out of the woodwork offering themselves to you.....
Even if there were a 10% gain in milage, the acetone would save you like $160 if you went from 20-22 mpg. I am still on the fence, but nothing ventured, nothing gained.
P.S. get a good funnel, and a glass or metal measuring cup, and possibly use the pint size containers of acetone because they are alot easier to pour without spilling PAINT THINNER all over the place. The stuff eats polycarbonate measuring cups like Rosie through a box of twinkies. Then there is the spilling it on you paint issue.