Doug, I think you are oversimplifying. Shooting Blackhorn and as far as that goes I have had them do it with 777, the flame channel from the base of the 209 to the touch hole carbons up. Now you can let it go until it causes misfires but most people like to clean it out with a drill an 1/8 inch if the BP has not been modified letting the BP carbon up past about 12 shots in most guns will affect both the group and the ignition. This is variable in some ways when I started modding my breach plugs I was working with this also that's why the flame channel in my modded BP are longer than the mods used by some of the others. I clean mine when I clean the gun after I shoot. You mentioned the threads, If the threads are wrapped right there should not be much cleaning involved if you are using grease instead of Teflon tape you have a bit more mess to clean up. If you use 777 be careful if is known to freeze BP's.