Originally Posted by
Utopian
I would assume that hydrolysis of the Aluminum Sulfate in the styptic pencil would produce sulfuric acid. That would be corrosive to your razor.
Regarding Thorxes' comment, after every shave I dip my razors in a solution of 0.5% mineral oil in isopropyl alcohol. The alcohol evaporates and takes water with it, leaving the oil behind to protect the blade. Because it's such a thin coating of oil, I never have to wipe it off before stropping and shaving the next time. I've had no ill effect on my strops after doing this for about 8 years. I'm not certain that it helps, though I think it does, but it doesn't do any harm.