I have a reoccuring problem with tarnish/corrosion on the 1/8" three-conductor connector of my XDT4 transmitter.  The tarnish causes massive crackling and popping to come through the guitar speakers when the cable twists slightly in the socket.  Periodically I pull the cable out of the transmitter and wipe it down but that only "fixes" the issue for a short period of time.  What is the cause of this?  What can I do about it?  The environment I use this in is dry and temperature controlled.

Thank you for your time and effort.