I am definatly going to try this. I will report back. 1996 Chevy Tahoe currently getting 14.69 MPG. Here is the link :http://peswiki.com/index.php/Directory:Acetone_as_a_Fuel_Additive Code (markup):
Acetone is not a good idea! (IMO) It will screw w/ your ECU, seals and oxygen sensors. No way would I add it to my car! if you need to do something like this, trade your car in for a Focus. Or go on a ramen noodle diet!
And of course, there's always the "Grease Guzzler": http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2000/08/09/MN85083.DTL