The dead have risen. You've found cans of tuna and old Mosin-Nagant ammunition. That's wonderful news!
. . . or it would be, if you had can opener.
Now what? Well, YouTube user CrazyRussianHacker has a trick that will let you open those vital consumables. All you need is a block of concrete. Rub the top of the can against the concrete until you've abraded away the top rim. Then squeeze on the sides. The lid will pop off.
-via Ace of Spades HQ