Salt is not a bad commodity choice for long term storage. It's useful for preserving meat, processing hides for leather, an alternative shotgun projectile, coating the rim of a margarita glass, tossing on the walks in the winter...all things that figure in to a post-Armageddon world. Perhaps condiment salt is the wrong choice for bulk storage- a bag of rock salt probably keeps better, or even a farmer's salt block. Nalgene is always the right answer for storing corrosives-it is one of the least reactive plastics, and nalgene bottles started life as labware for storage of hydrofluoric acid, which will eat its way through glass. Regarding access to mineral salt, there are salt mines in MI, KS, TX and NY (http://www.saltinstitute.org/14.html) I didn't know there was a salt institute-ain't the internet great?