for cleaning your connectors, etc, but they are a bit expensive
They run about 50 cents each. I get them from Dell for cleaning heatsinks and CPUs to put on fresh thermal grease. They usually send me two when I only need one, so I have a few.
My original Trailer Park (SN001) wasn't working, and I thought the switch was munged, then noticed I couldn't get the 510 adapter off. I plied it off and cleaned it up with one of these. While I was at it I also cleaned up the end of the 14500 No Ego, and even though it didn't look bad, green corrosion came off on the pad.