The acidity from chewing tobacco is what can cause problems.
Ahhh I see! Thanks for clearing that up. I must seem somewhat dense at time 
As a few others have mentioned, it really all depends on the type of snuff I’m sniffing at the moment. It seems like with the coarser Poschl’s I need to blow within ten minutes. I can keep medium grind (like Toque) in forever it seems, and the only reason I frequently blow a fine Scotch is because it makes my nose run. And then of course even after I think it’s all blown out, I take my nightly shower and even more comes out. Just depends on how big your shnoz is I figure.
@mikemoose I’m not entirely sure, but chew has TONS of sugars and (it seems) some sort of acidity that burns and sickens WAY WAY WAY more that nasal snuff. I dunno why, but I can handle snuff drip but chew is another story.
If nasal snuff gets swallowed it’s not gonna hurt you. You probably swallow MUCH MORE than you realize. 
@transistor : Yeah I think I do end up swallowing more snuff tobacco than I realize lol. I am glad it is not a cause for sickness. Damn man, honestly, I really love nasal snuff, it is my most favorite way to enjoy nicotine… Hands down