Many years ago when this nail clipper was new I needed to cut a couple of fine copper wires. I had nothing else at the time and I used my nail clipper. The wires made nicks in the cutting edges of the clipper. Eventually I learned a way to sharpen the clipper's cutting edges evenly and did so. (Ignore the surface rust that has appeared in the years since.)
The jaws will need to be held in position for sharpening. You need some precision difficult to obtain by using the actuating lever alone. Remove it by squeezing the jaws together with your thumbs or thumb and first finger, or with a pair of pliers as shown here. The lever falls out of the pin. Remove the pin.