I've seen several websites and youtube videos recommending to use an old pair of jeans to resharpen cartridge and DE blades.
Won't that wear out the blades prematurely?Hold your razor in your right hand as you would for shaving and place it, blade down, on a pair of jeans. Firmly swipe it across the jeans in the opposite direction that you would when shaving. Do this 10 to 20 times in the same direction. Switch hands and run the blade across the jeans another 10 to 20 times in the opposite direction that you would when shaving. This method of switching hands allows the jeans to rub the blades two different ways and sharpen the blades.