It was funny that you mentioned C Rats...
When I was stationed In the Navy in Puerto Rico as a Sea Bee, I found the stash of K-Rats in this big quonset hut attic space. Cases of it.
When I got hungry, I'd open the rations, and make deviled ham sandwiches on the canned biscuits, and eat the cheese and crackers.
I remember, I had 93 of those stainless steel little P38 can openers that came with the food kits. They were the greatest; never fail can openers. They were no bigger than a quarter dollar piece.