MIkey, rubbing alcohol will do wonders for removing oil deposits. Not to mention you get the rubbing alcohol into the catalytic converter and it burns nice and hot which will help convert the solid carbon deposits to CO2 (gas) and clear out the cat. Kinda like the light oil will burn hot in the cat, aiding in the removal of solid carbon.

 

This would be a minute quantity of alcohol in the form of a fine mist that spends a billionth of a second in the combustion chamber before combustion initiates. Never gets a chance to even contact the carbon deposits (which don't exist on healthy engines anyway)

The alcohol is already burnt long before it gets to the catalytic perverter, as is the oil and naphtha.

Modern gasoline contains more than enough cleaning additives (real cleaning additives) to keep any engine carbon-free.

 

That's why during the induction cleaning they suggest fogging the motor out until it stalls. I coats the system with the product. You let it sit not running for 20 minutes and then start it up and burn it off as you have suggested will occur. Treating the fuel treats the fuel system, not the induction system. It worked for my old Land Rover.