I was cleaning my lenses today, and I decided to brush/blow some dust off the mirror (no harm there). Unfortunately, the mirror foam disintegrated, and went all over the focusing screen. Some of it appears to have removed the etching (or whatever it is) on the surface, so I see shiny spots from outside, and darkened spots in the viewfinder. It's not bad enough that I can't use the camera, but it is very, very annoying. I'm not certain if the AE-1's focusing screen is even replaceable, not that I could find a new one anyway. I can't think of any way to fix this problem, either... So, am I screwed? Obviously I'll have to get the foam replaced (is it possible to do this yourself?), and probably live with the focusing screen problem.