rub out vs send to the glue factory

rub out

verb
  • To kill, especially to murder. 

  • To delete or erase or remove (something) by rubbing. 

send to the glue factory

verb
  • To kill, usually a horse. 

  • To retire or remove from prominence, usually due to obsolescence, old age or injury. 

How often have the words rub out and send to the glue factory occurred in a corpus of books? (source: Google Ngram Viewer )