Method:
Prepare a very flat glass or steel plate and some emery (abrasive particle size is above 320 mesh). Sprinkle a small amount of emery evenly on the surface of glass or steel plate to make water or engine oil drip. Put the bottom surface of the scissors blade on the flat plate, press the center of the blade with your fingers, and grind it in a circular motion or in a figure-eight motion. (Don't move back and forth, it is easy to cause the middle height to become warped left and right, and the cutter teeth won't bite tightly after installation, which will pinch the hair.
Key points: the intensity should be slightly larger and even. Do a circular or figure-eight motion.