He seems to have written his memoirs mainly so that he can 'dish the dirt' on all his former lovers.
The police 'struck pay dirt' when a witness came forward with new information.
The band 'hit pay dirt' [=had a big success] with their first single.
(..) ''l would ask him for cents, this man would tell me his life story.'' And my father never told a happy story. For cents there never was happiness. The man ate dirt till he was years old. That's all there was, was dirt. And he was thankful to eat that dirt. That's the part l couldn't understand. (..)1983 Bill Cosby: Himself