From everything I have read it is pretty much a waste of time. With the amount of very high pressure gas going through the tube each time, it is pretty much self cleaning. Well, maybe not cleaning, but self clearing. I'm sure that you can get some carbon off the walls of the tube, but I don't think it will affect anything. You hear of the tactical training guys shooting tens of thousands of rounds and they don't worry about cleaning their gas tubes. Heck, they will sometimes shoot a thousand or more rounds without cleaning the gun at all. Just add more lube and go.