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.
(..) Sheriff, why don't you go get yourself a quart of oil at Flo's. I'll keep an eye on him. Well, thanks, Doc. I've been feelin' a quart low. This ain't asphalt, son. This is dirt. Oh, great. What do you want? You here to gloat? You don't have three-wheel brakes, so you got to pitch it hard, (..)2006 Cars
(..) Lousy! Have fun fishin', Mater. Ah! I'm startin' to think he knowed you was gonna crash! Thank you, Mater. Thank you. I can make a little turn on dirt. You think? No. And now I'm a day behind. I'm never gonna get outta here! Hey, You need a new paint job, man! (..)2006 Cars