do in vs polish off

do in

verb
  • To kill or end. 

  • To exhaust, to tire out. 

  • To damage or injure. 

polish off

verb
  • To finish completely, especially a food (polish the plate with one's tongue) or liquor. 

  • To remove by polishing (rubbing with a fine abrasive). 

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