"It was my grandma's 95th birthday so I cooked for her. I asked her where she kept the salt and she said "I barely use salt, but if it's there, it's way in the back of the cabinet." It turns out the only container of salt she has is dated from 1965!!! It worked, and salt doesn't really expire!"The discussion thread at Reddit has a range of opinions on the use of salt in cooking.
Addendum, with a hat tip to reader Dragonmamma: