People often ask me what should I use to clean my RCA connection, I have used many contact cleaners in the past but the best contact cleaner I have come across so far would have to be one called Deoxit D5 manufactured by CAIG Laboratories Inc. I have used this on UHF wireless microphone aerials and the improvement is enormous. As for audio plugs and sockets, what more can I say, it's fantastic! It improves conductivity, deoxidizes oxide build up, seals and protects electrical connections. So don't get caught with poor connections, get yourself a can and use it before you start to hear noises.
Enjoy your music!!!