cable connector cleaner/contact enhancer

I have found that the following in some capacity achieves "cleaning".

(1) I use bare speaker wire. Perhaps once a year or so I will clip off the ends and create newly unshielded ends.

(2) in the case of rca or xlr, simply unplug and replug the connector. the "re-seating" tends to be desirable every so often, albeit infrequently.

(3) rubbing alcohol if some foreign matter is visible on the connector

bcowen, I agree with you on the rubbing alcohol. I mentioned "rubbing" alcohol previously but yes I too look or isopropyl or a high purity alcohol. Everclear is a pretty good choice :)
https://en.wikipedia.org/wiki/Everclear_(alcohol)