I have noticed recently that any exposed copper in my shop has a black, burnt look to it.
What is causing this? I first noticed it in my electrical panel, and thought I must have really overheated that circuit. Then I noticed it on the exposed ends of some scrap wiring I had around, so I concluded that wasnt' the case.
This is more than the usual oxidation that occurs over time on copper. Peeling back the insulation on said scraps of solid wiring, the first inch will have the discoloration, and the rest will still be the nice shiny wire.
Explanations? I assume a result of some cleaner or something I used, but wondering what.....
Thanks
JW