shitcan vs winter rat

shitcan

noun
  • A shoddy vehicle. 

  • A receptacle for holding excrement, especially the removable can on a latrine. 

  • A garbage can or wastepaper basket. 

winter rat

noun
  • An old, unattractive automobile, purchased for little money, to be driven during brutal Great Lakes winters while the owner's "good" car remains garaged and protected from corrosive road salt for the season. 

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