You don't have to clean the gas system. It's like a car exhause system but without emission controls.
If you are worried about obstructions you can use .080 weed eater line as a gauge and insert it into the gas tune from time to time to check for build up or obstructions
And if there were build up, how would one go about clearing it? I can see .080 weed eater line disturbing carbon and creating a blockage.