I bought a 16oz bottle at local Walgreens for $ 2.99, and put 4.5oz.
in to my 2000 Toyota Tundra (160,000 miles, meticulously cared for)
with a fuel tank capacity of approx. 21 gals.

These are the two observations that I am absolutely certain of:

1.) The engine is running much smoother at idle, and appears to have
more power.

2.) At idle, I've always noticed water dripping from tailpipe. After
running for 30 mins., and then idling for 10 min., the tailpipe was
dry as a bone, with absolutely no condensation or wet spot on any
kind. Also no noticeable exhaust in any form.

At this stage, it's too early for me to be able to guage any mileage
variance. But for me, the first two observations are enough to keep
using acetone.

Eventually I will try upping the concentration, but for a first try I
wanted to play it safe.