Alum block has been medically tested for being hypo-allergenic and are suitable for all skin types. In the unfortunate event of shaving nicks or cuts, place the block under cold water and apply to the area. The alum block is an astringent and antiseptic. It cools and refreshes the skin. This works equally well with electric razors. To learn more about shaving and grooming tips, check out other videos in this series.