expurgate vs lustrate

expurgate

verb
  • To undertake editing out incorrect, offensive, or otherwise undesirable information from (a book or other publication); to cleanse; to purge. 

  • To edit out (incorrect, offensive, or otherwise undesirable information) from a book or other publication; to cleanse; to purge. 

lustrate

verb
  • To make clear or pure by means of a propitiatory offering; to purify. 

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