Quoted from ChrisHibler:
"Cleaning" header pins if significantly tarnished, is not feasible. Simply replace them. If you sand them, you'll remove the finish and the "fix" will be short term. You can use a pencil eraser on them for light tarnish.
Hey Chris - I see your advice all over System 80 questions on here -- thanks a lot. While I have you do you have a source for the edge connector pins?
My Black Hole works perfectly now... with the exception of the sound. It's sometimes works fine, other times plays all the wrong effects at the wrong times, and sometimes locks on a hellish scream in the middle of a game, and I have to restart the machine to fix.
I have read over and over about connectors on System 80 causing such intermittent problems, so I was thinking of repinning A6-J1 (pictured).