There must be some rust on it. Scrub it well then put a thin coat of oil on it and put it in the oven upside down for a couple of hours on 300ish. I would wait until I was going to using the oven for something else and just let the skillet piggy back.
In the alternative...........does anyone else taste the metal? If it's just you then you may need to tell your doctor you are tasting metals.