An Owners Manual
This is an actual thing that happens in The Last of Us. You need to make shivs out of scissors and tape, and for most of the game, you can only use them once. Eventually, you find an instruction manual that allows you to use them twice before leaving them in the body of whatever you stabbed with it. What could that book possibly have said? And for that matter, would knives really be that scarce after the fall of mankind? I have at least a dozen knives in my kitchen that would work at least as well as a taped up scissor half for jamming into necks. What happened to all of them?