I replaced the cabin air filter a couple of years ago, and to do that I had to remove the glove box. I got an annoying rattle the other day and it sounded like it was coming from that area.after wasting a couple of hours taking that area apart I finally found the rattle.It's in the rear view mirror lol.Any ideas how to fix?And what possibly could be rattling in a rear view mirror?

 

I have the same damn rattle, I suspect the edges of the plastic shell vibrate with one another and create this annoying sound.
The only thing I can think off is felt tape over the edges so it's firm and making sure nothing else is loose inside.
Disassembly is the only way.