So how does one clean the inside of the front element(s?) of a 90mm Elmar? I also have a new-old Elmar. I could see haze in it after I shined a flashlight through it and thought I would try to clean the rear element. The locking ring was loose so I just unscrewed that, noted where everything was, and carefully cleaned the element. The haze came right off. It looks so much better I thought I might try the front - even though the lens looks clear. I just don't want to screw it up in doing so. I would be interested in how you did yours.