Possible Clues:

• Don't see so much of it if there's no dirt at all
• Dalmatians most unlikely to be this pure
• What unsuccessful twitchers do - honest!
• A teeny bit reduced, though clean
• Without a mark, completely clean
• Pure
• How you'll see fewer so clean as this
• Absolutely pure, clean
• How Lady Macbeth wanted to be above reproach?
• Irreproachably clean