How to Preserve New Shiny Banana Speaker Ends?

I've had the Nordost Blue Heaven speaker cables for more than 5 years now and the banana plugs have lost their shimmering gold finish. I have never cleaned those plugs within these years but just lately bought some Progold cleaners hoping to bring back the glitter but alas...I realized it's too late as oxidation has taken its course. The previously golden plugs now looked a bit black and don't look too good although soundwise is not an issue.

Since I've recently bought a brand new pair of SPM speaker cables, I am hoping to preserve the banana ends to their sparkling gold condition as long as I possibly can. Will cleaning the plugs periodically, say once a month work? I just hate to see them turn black.

Your opinions are much appreciated. Thanks in advance.
Strange because my MIT cables are 6 years old and have shiny gold on them with no sign of oxidation anywhere. And I haven't seen any other of my cables go black. Besides, it is very tough to oxidize gold - in fact, it has the lowest tendency to react with air to form oxides of any element on earth.

Are you sure that the black isn't actually muck encrusted 'on' the ends rather that 'in' the gold? Maybe rubbing alcohol would remove it (or acetone) although I assume the Progold should have taken care of it. Hmmm...keep us posted.

Maybe my description does not convey the message across clearly. I'll try again, and sorry for the lack of terminology.

It doesn't sound as serious like the plugs have gone entirely black. It's still gold but there is a slight hint of discolouration towards blackish gold. There isn't any extra layer on the plugs. It's just that the gold somehow doesn't look as new as they were during the first time I've got them. I've taken for granted I didn't clean them for a single time in 5 years that may have caused them to lose the shine. This not only apply for the speaker ends but also to the speaker terminals of my old pair of speakers.

Well, I guess there is a reason why NEW is good. Or maybe I've not taken enough care to preserve the condition? I don't think I can get back the shine to the plugs as new but guess I'll have to use Progold more often on not only the speaker ends but also to all my electrical connections of my equipment.
Try one of the least abrasive Scotch Brite pads or some 400 grit sand paper. If you don't like the idea of abrasives you might try a Mr. Clean magic erasure. They have cleaned almost every thing I have thrown at them.
FWIW. Its my understanding that the only real benefit from using gold (plated) anything is to allow more efficient conductance of current AND to make this effective both surfaces should be gold. So if your speaker connectors are not gold plated its not a 'deal'.

Your bananas are gold plated and what you are probably seeing is a wearing off of the gold plate from use. It could be a build up of gunk but I doubt it.

Also, consider, by adding any lubricants to your connectors you may be inviting the accumulation of gunk.

Personally I focus on keeping the connections as tight and clean as possible. If you are not already doing so consider using locking banana plugs.

Well, if losing the gold plate bothers you, just get some MIT cables. :)

Newbee has it right in my view. Gold does not oxidize; that's one of the reasons why it's used, that plus its' conductivity. If it's darkening, it could be a build up of some of gunk which can be cleaned off with something like Caig Progold. Otherwise, the gold plating has simply worn off. As you probably know, one of gold's other characteristics is that it is very malleable. It can be stretched very thin. Some gold plating is only a few atoms thick!
Thanks for responses. Yes gold is an element that doesn't oxidize but I have the impression that the plugs must be metal or something, and the gold is just coated on it. Just checked on the specs of Nordost Z plugs(for the 1st time in 5 years since I first used them), and those plugs are berrylium copper, gold plated. I believe the gold has worn off slightly, revealing the copper beneath. There is just no way to preserve the gold finish from wearing off due to friction of frequent plugging/unplugging those plugs isn't it? Hmmm guess Aball's recommendation of getting some MIT cables may worth considering!