graveclothes vs plain brown wrapper

graveclothes

noun
  • The clothes in which a corpse is buried. 

plain brown wrapper

noun
  • Any veil, disguise, or mask. 

  • An act of dissimulation, camouflage; a cover-up. 

  • An obscuring cover or wrapper, originally to allow postal delivery of sexually explicit periodicals. 

  • An unmarked police car. 

How often have the words graveclothes and plain brown wrapper occurred in a corpus of books? (source: Google Ngram Viewer )