I would carefully remove the built-up carbon from the exhaust port. don't get it in the cylinder.
Yes I installed my new block off plate and cleaned all around there. Dad was into electronics..I found out years ago the old TV adjustment tools work great for tight places. There are a bunch laying around. Has flat blades on both sides, with one smaller blade.
And dad had a whole drawer of old school medical Q Tips...the bag is so old it is stapled at the top of each bag. His friend used to be a surgeon, so I also have a bunch of cool forceps in different lengths..someone mentioned using some to install the impulse line..perfect because I have a variety.