What to say if they ask me what I am gonna do with SN?

[Coyote]

What are the other areas of usage that makes sense to tell if I am asked?

 

[MyrSS]

Mostly people only use it to preserve stuff. If you're in a place where it's kinda normal to hunt say you're going to use it to preserve meat you're gonna hunt I guess

 

[Fehler]

The question is that it is credible depending on your case. Would they believe you? Have you gone hunting? Do they know you like chemistry? For example (although I don't have the problem that they find it) I would say that it is to try to make wine (since I already made mead a long time ago). As you have been told, the main use is for canning meats, would you say that you want to create your own bacon? Anyway, if they know your "situation", I don't think you are going to fool them so easily.