Anyone have any ideas on how to SAFELY clean the inside of the muffler? I noticed some performance issues and read to clean the Spark arrester. That was caked with carbon buildup! After cleaning I changed the airfilter and noticed a slight performance increase. I was wondering if it is possible to and if it is worth cleaning the muffler and how to do so. I know there is a way to use the drain plug as a way to "clean" but I would like to give it a good deep cleaning. Thanks!