What happen if I damage focusing screen on my canon AE-1 and question regarding mirror foam?

Question

I cleaned my Canon AE-1 last night, some of the old foam got smeared into the focusing screen. It was hard to clean, I had to put alcohol several times and use cotton swab to clean it, and it was "kind of" clean. Today I read several articles about how fragile focusing screen is. My concern, did I damage my focusing screen ? What does damaged focusing screen do to the camera operation, especially manual camera like AE-1 ? I looked into the viewfinder, there is no scratch except little of smears from the foam.

My other question:

Do I need to replace the foam ? What happen if there is no foam ? will the mirror crack ?

Thank you for your help.

Answer 1

You will need a professional to put your camera back right.

I don't know what spurred this cleaning frenzy, but if you ever get the urge again, read this.

http://www.kenrockwell.com/tech/cleaning...

Answer 2

As far as the focusing screen goes, thats replaceable.  

The "mirror foam' are light seals designed to not allow light passing through the viewfinder to hit the film while the mirror is in the up position.  If its significantly damaged you will see odd spots of light or overexposed pictures.  If its really worth it to you, have the camera professionally serviced, but be warned that wont be cheap.  

Answer 3

Other than inconvenience on focusing, there should be no affect in the camera operation.

If you really concern, you can replace the focusing screen without any problem because AE-1's focusing screen is interchangeable.

However, it is a 30some years old design, you might have a hard time to find the replacement screen.

Do try eBay, Craiglist and local camera shops' used department.