I just received in my first shipment of tinned tobacco from 4noggins.com. How long can I keep it in the tin, A. if its unopened and sealed, or B. if I open the tin? My office smells amazing right now and I really want to crack them open to smell them, but I'm pretty sure I shouldn't. I received in Dunhill EMP, Escudo Navy De Luxe, Erinmore Flake and Captain Black Royal (along with my new Zippo pipe lighter).