Factual error: The ferry carrying Ziva and Tony to the aircraft carrier should have the Italian merchant flag, but it has the national one (this flag hasn't got the shield drawn in the middle).
Continuity mistake: When Tony & Ziva meet their contact in Naples, we see a local cop walking down the background behind them, and passing a walkway to the boat. Seconds later, as the camera changes view, we see that cop about 30 feet back, going the same way.
Chosen answer: "Policing your brass", means to pick up your expended shell casings, after firing your rifle, or pistol.
pross79