Makes me appreciate a correctly installed and sealed air filter. Now what happens when someone sprays some sort of carbon remover down the intake of a running engine to remove carbon from the intake valves? I wouldn't do it.
see video here
https://www.youtube.com/watch?v=NwIjLECJmA8
see video here
https://www.youtube.com/watch?v=NwIjLECJmA8