Does unused oil go bad?

Oil doesn't spoil if its unused and sealed in a bottle. It starts to break down when it gets contaminants like combustion byproducts or gasoline in it.

You didn't say how old it is, either. If its in the old cardboard cans, then it is more obsolete than spoiled. The base stocks and additives have improved leaps and bounds in the last 25 years. I'd use it in a lawnmower or beater car, but not just toss fresh oil to the recyclers.