butchering vs knacker's yard

butchering

noun
  • The act by which someone or something is butchered; a slaughter or killing. 

knacker's yard

noun
  • The area of a slaughterhouse where carcasses unfit for human consumption or other purposes are rendered down to produce useful materials such as glue. 

  • A (notional) place to send a person or object that is spent beyond all reasonable use. 

How often have the words butchering and knacker's yard occurred in a corpus of books? (source: Google Ngram Viewer )