I was recently in an old country store and I was scanning the shelves for any vintage shaving items (none found), but I spotted a can of powder alum, it was in a spice looking can, and from what I've read it is used for making pickles. Has anyone seen this and considered using it instead of an alum block? I also considered getting it and disolving in Witch Hazel to make a super aftershave. Any experiences with this?