Originally Posted by
vileru
Whether you should use it after every shave is something for you to decide. Try it out, and decide for yourself. The same goes for whether to leave it on or rinse it off. However, most people, including myself, seem to prefer to rinse it off since the astringency can become uncomfortable.
One thing that no one has mentioned: make sure to dry off the alum block after use. If you leave it wet or on a wet surface, alum crystals (that are more or less useless) similar in appearance to salt will form on the alum block, which will drastically shorten the life of your block.