Tube socket cleaner, while browsing a make up store a couple of weeks ago ...
Came across some free sample eyeliner brushes, that does a great job of getting into all but smaller (like 9 pin) sockets. Spray a bit of your fav contact cleaner and poke and twirl away. Should make a difference having clean contacts, mine were clean already, so no difference. The kind staff informed me that I could grab a handful and that most make-up type store have them.
Cheers,
Ian