silver top vs twirly

silver top

noun
  • An old person. 

  • Full cream milk, normally homogenised and pasteurised, having a silvery top to the bottle. 

twirly

noun
  • an old age pensioner or other elderly person, especially one using public transport. 

adj
  • coiled or curly 

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