I met a gentleman at SEMA that is a fuel system engineer from GM.
I asked him about the validity of all these little fuel saving things that people come up with like adding acetone or alcohol to the tank. He told me that if little tricks like that actually worked, then those types of fuel would be available then. He also said that modern car's fuel systems are designed for certain combustable materials and using other chemicals that they are not designed for, will most certainly damage internal parts. Especially since the car's computer reads the exhaust gases and adjusts the ignition and fuel system accordingly. If the addition of another chemical causes abnormal readings, the computer will not tell the engine how to run properly.