I like Caig ProGold from www.audioadvisor.com. Not only does it clean the contacts, it leaves a thin protective coating.
How to clean RCA inputs and outputs?
In the past few months I have purchased used audio equipment from AudioGone, AudioWeb, and eBay. All vintage from '70s & '80s. Almost all input and output jacks are covered with a dirty film, grunge, or slight corrosion, especially the unused RCA jacks. What is the best method and cleaner to safely use? Any suggestions would be appreciated. Thanks.