NeilM":3v5fokte said:LBS should be able to run a tap through the BB, or you could get as much surface paint off as possible and then use old BB cups to clear the threads.
As for the bosses and stem. I'd be inclined to use emery cloth, as you can use it in fine strips to just work on the bosses. Look at how any of the frame builders smooth out fillet brazed joints and you will get the idea.
Yeah good point. It's just so annoying. For someone who builds at a snails pace, its not good news either!