I too have dug thru the trash looking for a pack that I threw away. Once I threw a pack out of my car window and swore I was done and five miles later pulled into a store and bought another one.
I had spilled a pack in my car, I ran out a couple of weeks later without a chance to get more, dug under my car seat and found one of them. It had been sitting under my seat, was quite stale, had some unidentified substance on it, but I still smoked the thing.