I'd like to hear what people have to say about this too. My dad's toy hauler, when bought, already had yellow windows. It sat on the dealer's lot for a while. I haven't tried anything other than Awesome, which helped some, but it didn't turn them completely white again. You could try Awesome, just realize it won't get the yellow out completely. I guess my only suggestion would be to see if you could pull off that trim and paint it white.
Jon