Hey-Hey!!!,
Pardon the pun, but a Q-tip makes an excellent cleaner for old RCA jacks. I peeled 95% of the cotton off, and applied a little bit of polishing wadding. Stuck the other end in a hand drill and spun it. Nothing like the proper power tool for a sensitive job! Don't put too much of a ball into the end, as it might bend the inner contacts. Clean with a 70% peeled clean Q-tip( by hand ) and then peek inside when you're done. Nice clean, shiny contacts...:)
cheers,
Douglas