Has anybody heard about putting acetone additive in your gas improving gas mileage?

My dad did some research on it, and apparently he's been doing it for about a month now and has seen minor improvements.

He was getting 18.0 MPG on his 2001 Supercharged Bonneville (SSER)
Now he's at 19.4.

He also said that, because acetone helps to burn your gas more efficiently it helps reduce carbon build up.

Any thoughts/experiments people have conducted?