I have used the screwdriver trick about a dozen times to remove my corners and it works great.

 

use the screwdriver, BUT not between the edge of the fender and corner. Wrap it with cloth, then pry it at the part that had the screw hole, that plastic extension(thats where the tip should go), then pivot the side of the screwdriver on the inside part of the fender and pry forward while using your free hand to push it forward also.