If those stains are really internal, do not try to clean them yourself. Send those pics to Roland. I've never seen (or owned) an AP lens remotely as screwed up as that one. Oil spacing: you can prove it for yourself. How many reflections can you see in the lens? Two? That's one per air-glass surface. If you had an air-spaced lens you'd see six. The oil is a very thin film between the elements. The whole lens assembly is sealed with some sort of fancy tape (Kapton?) You will court, and probably successfully woo, disaster if you try to deal with this yourself.
-------------------- Seven telescopes of a diverse nature.
Multiple chums glittering in the sky. New friends await.