How do you remove a screw guard?

Insert the tip of a flat-head screwdriver into the cut slot. Press down firmly on the screwdriver while turning the one-way screw counterclockwise until the screw is out of the window guard.

How do I remove mylar screw covers?

To remove this screw, use a regular philips driver and puncture the mylar cover. Once the mylar caps are removed it cannot replaced, and the screws will be exposed from that point forward.