On another thread about cleaning the bolt, someone recommended using carburator cleaner for cleaning. I was on my way out the door to walmart to get some when I remembered that I had a case of fuel injector cleaner in the garage which is probably the same stuff. I decided to try that instead but couldn't figure out how to apply it, especially to the small crevices and holes. I decided to drill out the nozzle of an old plastic spray bottle and inserted the straw from an old WD40 can into the hole. I made the hole slightly smaller diameter than the straw to give it a snug fit so it wouldn't come out. It worked like a charm, so I squirted the fuel injector cleaner into the piston hole and all around the gas block. I couldn't believe how the carbon dissolved with almost no scrubbing. I then sprayed the receiver, op rod, and barrel with it and everything came out shining. My 25 year old 183 SS now looks like new. I'm going to try it on my revolvers and 10/22's now.