Tried it. Don't see the point.
I rarely use it on my face, but always use it on my hands when I handle a razor and do skin stretching. It works wonders for this application and without it, I feel like I can't keep a good grip.
I use alum after the cold water splash. I let my face dry while I'm cleaning up, then rinse the alum off with more cold water, followed by witch hazel. Let the witch hazel dry, then AS.
How long do you guys leave the alum on after a shave? I noticed the longer I let it dry before rinsing and applying AB, the longer it takes any redness to go away. Now, I'm talking the difference between initial redness going away in 30 mins vs. 1 hour or so. Although not that bad, long enough for you to shave and end up at your destination still with a bit of red areas one our face.
only con I can think of. or if you had a rough shave with some irritation it will burn. burns like an AS would, nothing greater, and eases up just as fast.
it will teach you how to develop a technique that leaves less irritation.