How do you get those two little air vents off that are right next to your doors on the dash of a cavy?
 
get a small flat head screwdriver and pop them up there held in with a adhesive i think atleast mine were!
 
 
You have to be careful, they have a lot of adhesive/glue holding them in.  I popped them off when I took my dash off.  I broke the glue from underneath, and just popped them off that way.  If you pry with a flathead screwdriver, it should work just as well.