Slide the blade in under the metal strip and get the sharp point up between the clip and the rolled edge of the trim (next to the car body). The trick is to spread the clip, so you can drive the point further in or try twisting and/or prying, but be sure all your work is between the rolled edge and the inside barb of the clip. Once you get one, the rest will be easy because you'll see what you're up against.
