clean as a hound's tooth vs spotless

clean as a hound's tooth

adj

  • Very clean; very innocent. 

spotless

adj

  • Exceptionally clean. 

  • Impeccable and free from blemish. 

  • Lacking spots; unspotted. 

How often have the words clean as a hound's tooth and spotless occurred in a corpus of books? (source: Google Ngram Viewer )