Mr. Monk and the Red Herring - S3-E10
Continuity mistake: When Natalie puts out the fire with the extinguisher, the nozzle is still pushed down when she uses it, but when she puts it on the table, in the next shot the nozzle is fully extended. There are a number of times during the scene, when Monk is trying to figure out how to use it, where the nozzle's position keeps changing between shots.
Mr. Monk and the Red Herring - S3-E10
Continuity mistake: At the science fair, after Lyle Peck lights the poster on fire he puts the Bunsen burner onto the table a little away from its original position but when the camera angle changes it is back where it originally was, under the beaker and stand.
Mr. Monk and the Red Herring - S3-E10
Continuity mistake: Monk empties a pocketful of pushpins onto the science teacher's counter top. One rolls to the very edge, separate from the others. A few minutes later, the stray pin is missing. Just before Monk and Natalie leave, however, it reappears on the counter edge.
Mr. Monk and the Red Herring - S3-E10
Continuity mistake: When the coffin Monk is in is opened, he has candle wax on his hands. In the next shot, there is no candle wax.
Mr. Monk and the Red Herring - S3-E10
Continuity mistake: In the pet store, the bird's cage has a plastic covering on the sides. But in various shots, either one or both coverings are missing.
Suggested correction: This is wrong, it was just the way the camera angle made the cage appear where I couldn't differentiate the space between the bars, so it looked like there must have been a covering.