I just cleaned the sensor and the white plastic fell off!

I just cleaned the sensor of my 300D. And when I shut the camera off (it says to shut off camera after cleaning is done) the plastic piece and the metal clip that holds it off above the mirror (when not in cleaning mode) fell off. I just pushed it back in.

Should I be concerned? Should I clean that plastic piece too? There seems to be dust in it. I'm not sure if I can get my fingerprints on this plastic piece too.

Any help would be appreciated. I don't have the manual since I bought this camera used.

Everything seems to be fine since I pushed that plastic piece back in. Just how delicate is that plastic piece?

P.S. Is there a name for this plastic piece?

Thank you.

That would be focusing screen.
You can clean it, but usually a squeeze or two from the rocket blower will be enough to take away dust bunnies.
If you didn’t turn it upside down when you put it back, everything should be fine.

Try focusing on some near, close up detail using wide open aperture, just to check if auto focus works properly.

http://www.usa.canon.c​om …tegoryid=314&mo​delid=9430

Use that link and then click Product/Software manuals to download a .pdf of the manual for your camera, for future reference