well i was thinking you could inject it into the fuel supply right before, or at the fuel filter, right before the carb. i doubt acetone would be able to do much damage while the engine was running, but if it was to sit in the carb all night, i'd be afraid it'd do some damage. you would want a way to turn it off about 10 seconds before you shut the car off for good too to keep it from sitting in the cylinders. it might not do much damage, but it would make me feel better to have a button to have manual control.
the only problem would be metering.
i cant see how you would inject such a small amount of acetone into the fuel acurately.