I am replacing my front driver's side fender liner. Easy going until I reached the bottom, rear part where two rivets are holding the fender. One I "solved" by tearing the fender off the rivet -- although I need to use the rivet to reattach the new liner. The second rivet is behind a piece of sheet body and will not put up with any nonsense from me. They are both the same type: they look pretty standard, with a central head that pops out with a screwdriver. The body though is a flat plastic plate about 1 cm in diameter on the outside that I can see, and some intrusion into what looks like a plastic rectangle from behind. These bodies do NOT just come out like a normal rivet. Here is a photo of one of them, after the head has been removed: What is the trick to get these guys out ? Thanks!
