Do cables age or become too old at any point?

I use to work with copper that was 99% pure. We worked with copper plates and I noticed a few things. If copper gets wet it will start to show corrosion in as little as twenty minutes. Im not talking under a micrescope but right in front of your eyes.

Second if the plates were stacked on top of each other they would stay shiny for several months, even over a year, but if left in the open they would start to tarnish and dull in just a couple of weeks.

I dont know what any of this means but I thought I would pass along the observation.

It should probably be pointed out that the corrosion visible through a clear jacket maybe wasn't caused by the jacket itself, but was the result of such an old cable's having been made using copper that was not pure by today's standards. My head hurts now....

Perfect, what would happen if you stacked a copper plate on top of a zinc plate using a peeled potato between them as dielectric ? Inquiring minds want to know : ) Sean
>