How to get the razor blade faster?

There are two kinds of razors, one is the razor, the blade of the kind of knife has no way to sharpen faster, can only be replaced. The other kind is resting on the knife frame, such as the Eagle brand, this blade can be ground. The method is: use a glass cup, put a little water inside, the cup is slightly tilted to press the blade on the inner wall of the cup, repeatedly grinding back and forth, so you can grind the blade fast.