that is not uncommon here in the great Pacific Northwest. It is usually Munster like wire and it can be so bad the conductors corrode the whole length of the wire and it "crunches"when you bend it.It is worst near the ends.You then have to cut the ends back untill you get less bad (it's never good)wire. Replacment is your best option if possible. Your best bet is some better brands of wire (Belden,Liberty,Audioquest,Comscope,etc)