deep six vs obliviate

deep six

verb
  • To discard, get rid of, or cancel; to completely put an end to something. 

noun
  • Ejection, discardment or destruction. 

  • The grave or death; also, the (notional) place where something is discarded. 

obliviate

verb
  • To forget; to wipe from existence. 

How often have the words deep six and obliviate occurred in a corpus of books? (source: Google Ngram Viewer )