Silver plated copper

geoffkait you are correct.A coating of oxidation does protect the rest of the wire.But the ends need to be sealed with something or they will degrade and not pass the signal properly.The good news is that it takes a very very long time to get to that point.

That’s what Deoxit and similar products are for as well as contact enhancers like the graphene paste. No big deal. Audiophiles are pretty well versed in electrical contact housekeeping protocols.

Just to clarify for everyone on this post - Copper oxidizes very rapidly but Silver does not.

A clean Copper surface prepared in vacuum forms a monolayer of Copper Oxide within minutes of exposure to air. A clean Silver surface prepared in vacuum forms a fraction of a monolayer of Silver Sulfide within minutes of exposure to air but no oxide within that timeframe. The tarnish observed on Silver is primarily Silver Sulfide.

As a long time coin enthusiast, I can say without doubt that copper oxidizes much quicker and to a greater degree than silver. Coin grading services even designate pristine examples of uncirculated pennies as a mint state condition with the additional designation of "RD" which means red. A penny so designated will command a price several times higher than one designated "BN" which means brown. On the other hand, bags of uncirculated silver dollars (90% silver, 10% copper, minted from 1878 to 1934) that have sat in bags of one thousand coins in bank vaults and never seen circulation will still have the original mint luster just like the day they were made, even over a century later. In fact, any oxidation that does occur on those dollars many times results in a multi colored rainbow sort of hue, and those coins command a premium over the mint luster shiny ones. Ironic that oxidation on silver coins commands a premium price while oxidation on copper coins degrades the value.