If it's "medicated" snuff, there's also the possibility of camphor as being the culprit. I don't know how many medicated/menthol snuffs use camphor, but I know some people can be a little allergic to it. I know McChrystal's O&G uses camphor.
Still shouldn't be getting on the tongue though. If your nose runs when using snuff, just wipe it with a handkerchief (don't use paper towels, too abrasive, even Kleenex type tissues are a bit too harsh to me), don't try to snort the snot up into your nose or suck it down your throat.
Still shouldn't be getting on the tongue though. If your nose runs when using snuff, just wipe it with a handkerchief (don't use paper towels, too abrasive, even Kleenex type tissues are a bit too harsh to me), don't try to snort the snot up into your nose or suck it down your throat.