Never did see pure water, BUT I did witness atf and water, about half and half mixed by shaking the Coke bottle before it was drizzled into the carb with the engine at about 2500rpm, not killing the motor in the process. Was alleged to get carbon out of the combustion chamber. Smoked a lot, but after a short drive, the smoke was gone.
MANY of these orientations tended to be fueled by what might be available locally, rather than going to a formal auto supply for supplies. ATF was everywhere at filling stations and such (which also did light mechanical work (as tune-ups) back then. Pure water might have been for the people "out of town", whereas the atf + water could have been for the "town people" who did not want to spend the $1.50/bottle for Berryman's B-12 additive. To me, the atf + water would be a safer mix!
ATF in the motor oil was alleged to work as a cleaner due to its lighter viscosity and the fact it had a different betch of detergents in it than normal motor oil did. In the 1960s, the best motor oil was not nearly as good as the cheapest motor oil now, as to detergency. Aside from the detergency, the 1qt of atf thinned the norma motor oil, too.
Back then, "borescopes" were not around so no way to look inside to see how much carbon was gone. The old "vapor injectors" kind of operated on the same principle. Alcohol and water were in the container together and the mixture was metered into the car as it ran. Was supposed to increase power and mpg, but the people who I saw have them on their cars back then didn't keep them long. Such a mixture was needed on the '62 Olds Jetfire V-8s as it was factory turbo'd with a 10.0 CR. They called it "Turbocharger Fluid".
Check out the "Chris Fixx" YouTube videos on fuel system cleaners. Borescope images.
CBODY67