That icky cake buildup in the bowl of a cob has to go too. I use a half round bastard file and finish with 200 grit drywall mesh sandpaper. As soon as I see brown I'm done. Paper towel and that's done. Definitely swab the shank with alcohol soaked pipe cleaners until it's coming out clean. Lots of other tools to clean the cake out too. Flat file on edge will do it without hurting the pipe too.
I just wanted to comment I really enjoyed saying "bastard file".
