Kissing one’s mezuzah seems to be an almost universally accepted custom nowadays, at least among Ashkenazim. However, I once heard it was the minhag of R. Hirsch to simply look at it and meditate on its content, without touching the physical box, whenever one passes a door with a mezuzah attached.
Nevertheless, I’ve never found the actual source of said practice, and now I’m afraid it might not be true at all. Maybe it was just my wishful thinking to have an established tradition that was against kissing mezuzot, as I find the act a bit unhygienic.
Any ideas regarding the factually of it all?