
Continuity mistake: When Gibbs drops the nails on the food carton, the position of the nails goes from spread out to grouped together instantly. (00:19:50)
Once a Hero - S4-E8
Continuity mistake: When talking to Luis, his ID badge keeps moving and rotating without touching it. (00:08:20)

Witch Hunt - S4-E6
Continuity mistake: McGee is taking some photos of 3 bullet casings on some wood flooring. Take note of the casing to the upper right. Its position changes with no-one touching it. (00:06:20)

Continuity mistake: When Tony is going through the drawer there is nothing red in the overhead shot. However in the close up there is a red folder in the drawer. (00:06:20)

Singled Out - S4-E3
Continuity mistake: When Ziva is pointing at the map and explaining about how the driver was tailed, she is pointing with her right arm. Camera cuts and now it's her left hand. (00:20:35)

Singled Out - S4-E3
Continuity mistake: Tony places the blue folder in Jenny's tray on her desk neatly. When he goes to leave it is now propped up on one side of the tray. (00:04:25)

Singled Out - S4-E3
Continuity mistake: When Tony is talking with Jenny about Gibbs, he has his hands clenched up by his chin in the over-the-shoulder shot and down in his lap in the front angle. (00:03:25)

Continuity mistake: Fornell gives Gibbs a juice box when Gibbs stays with Fornell. Gibbs puts the straw into the box with the straw closest to him. Camera changes and now the straw is at the other end of the box. Since there is only 1 hole for a straw on a juice box it is clear the box has turned around. (00:25:35)

Continuity mistake: When Fornell and Gibbs are talking in Gibbs' basement, Gibbs places a red storage box on some wood and there is a fair gap between the red box and the cardboard box that is next to it. When the camera changes, the boxes are almost touching with no-one touching it. (00:04:15)
Continuity mistake: When agent DiNozzo and agent Sacks are arguing on the stairs, Sacks proceeds down a flight of stairs. Director Sheppard then calls both of them to the top. When the camera changes, Sacks is level with DiNozzo despite having descended a flight just seconds before. (00:13:30)
Chosen answer: "Policing your brass", means to pick up your expended shell casings, after firing your rifle, or pistol.
pross79