It was rusty FAR beyond any expectation of finding any Budweiser in it.
Would have gone flat anyway.
My only surprise is that it wasn't ALL rust. The soil out here in the cedar woods is pretty acid. Maybe not as much as the Michigan oak forests, but quite acidic. And this can had to be OLD -- I think by the end of the 70s cans were all alumin(i)um and outfitted with various unsuccessful pop-tops, some of which would slice open a finger.
I remember opening a soda pop for my parents using a proper old can opener. Some times I even used one to open whole cans of food....they were brilliant. Start punching, and punch around the top until the whole top was off. It may have left a sharp lid and can, but it worked every time.
....outfitted with various unsuccessful pop-tops, some of which would slice open a finger.
LOL, some of us are probably not recognizable from our birth fingerprints because of those things.