I use it as a fuel stabilizer sometimes... it also helps de gum a carb if someone forgot to drain the carb before letting the bike sit for several months... I always try this and most the time it'll work after the engine has run a few minutes, if not, then it's time to remove the carb to disassemble and clean properly.
As far as pouring it thru a 2 stroke engine to de carbonize... not such a good idea...
Still, the best way to de carbonize the combustion chamber or piston crown is good plain Ole h2o... the steam produced will make short work of carbon deposits that can lead to scratched cylinder walls and piston skirts. There are better ways to boost compression than letting carbon build up, a little blackening on the piston or combustion chamber won't hurt, but a lot will break off and does nasty things to the cylinder and piston skirt's over time.