@corelli :+1! Green oxidation was a problem with the old clear Monster Cable speaker wire! I had to throw away a bunch of it! No good! It didn't affect sound quality though! Not acceptable for the high-price Sunyata power cords!
Corrosion
On a Shunyata Diamondback power cable I use, which has clear insulation, there is green oxidation visible on parts of the shield. Can that have an audible effect, is it a concern?