If you think she only did it for the money, you haven't even 'scratched the surface'. [=there are many other factors, reasons, etc., involved]
Despite the 'surface' differences between the two candidates, they are very similar in most ways.
The tension between them is beginning to 'rise to the surface'. [=it is becoming easy to see]
(..) It's not enough that we got her two henchmen. Must be a vast network, John. Thousands of operatives. You and I, we barely scratched the surface. You cracked the code though, Sherlock. And maybe Dimmock can track down all of them now he knows it. No. No, I crack this code, (..)2010 TvShow: Sherlock Title: The Blind Banker Season: 1 Episode 2
(..) WOMAN: The great artisans say the more the teapot is used the more beautiful it becomes. The pot is seasoned by repeatedly pouring tea over the surface. The deposit left on the clay creates this beautiful patina over time. Some pots, the clay has been burnished by tea made over years ago. (..)2010 TvShow: Sherlock Title: The Blind Banker Season: 1 Episode 2