I was given a nice old 10" cast iron skillet from the 1950's. Only problem is the former owner sprayed it with WD40 in his garage so she wouldn't rust. Any chance of bringing it back?
Congratulations on this excellent find. Burn it. Build a wood fire in the backyard and burn it. Do not spray water on it while it is hot. Allow it to cool slowly. Wash it well and re-season it using Crisco soon after it cools.
My grandpa did this, my father did this and so do I.