Throwing ATF in the crankcase or gas tank(makes a great octane booster) is a tried and true method for carbed engines.Do not use on newer FI engines as it will destroy the fuel system since ATF softens rubber and there's alot of rubber o-rings in your fuel system in a FI engine,same goes for acetone.
Oh and misting water from a spray bottle into a running engine with either a crab or FI does wonders also,works better with windshield washer fliud though and don't use to much,just mist in.
There used to be an old fellow that always had a stand at the county fair every year. he sold this device he made with a rubbermade bottle and some tubing that would be connected to the cars vaccum system in such a way that it made a mist of the solution of windshield washer fluid and Isopropyl alcohol that got sucked in to the intake. He claimed your car would run smoother and use less fuel. I tried it on my carbed Isuzu I-mark and it did run smoother after only a day and from then on untill the bottle cracked from heat under the hood. after that I disconected it.