flattery vs soft soap

flattery

noun
  • An instance of excessive praise. 

  • Excessive praise or approval, which is often insincere and sometimes contrived to win favour. 

soft soap

noun
  • any fluid or semifluid soap 

  • jellyish soap made by cooking natural oils and fats with potassium hydroxide 

How often have the words flattery and soft soap occurred in a corpus of books? (source: Google Ngram Viewer )