Having bought this tool some weeks ago I have only recently been able to use it. But I can honestly say this is the best thing I have ever used. Using the brush attachment and a spray of oil into the chamber area the way the brush is designed it gets around all areas of the chamber including in between the locking splines. This will turn the brush black just as well it comes with a bag of 10 extra heads. And the dirty heads are easily cleaned with some white spirit. Once you have used the brush you can then use the flannelette on the main tool instead of trying to use you little finger much better results and no sore finger from doing it endless times. You will be hard pressed to find an NCO to find dirt in the chamber after using this tool! The pin tool is also very useful in the cleaning process it will help remove carbon from all areas where a fine point is needed. Very useful on the gas area I removed a large lump of carbon that the other tool provided could not reach. All in all this saved me lots of time and effort with a very good result very pleased with this.