Johnny: Hey, look at us, son, a couple of working stiffs back from the salt mines.
David: What?
Johnny: Two men, back from the mines.
David: What mines? What's that mean?
Johnny: It's a figure of speech.
David: Um, I don't get that.
Johnny: The salt mines! Back from when people mined.
David: Uh huh.
Johnny: When miners worked in the, salt industry, they'd come home, after digging salt. I don't know what it means!