put lipstick on a pig vs spiff up

put lipstick on a pig

verb
  • To superficially alter something in the hope of making it seem more appealing than it is in actuality. 

spiff up

verb
  • to decorate or otherwise make more attractive. 

How often have the words put lipstick on a pig and spiff up occurred in a corpus of books? (source: Google Ngram Viewer )