Visible crew/equipment: In "Playing The Ponies" (1937), a man eats a handful of hot pepperinos, and his mouth is burning. He quickly drinks a large container of water. The hose that drained the container is visible below his right arm.
The Three Stooges Show (1960)
1 visible crew/equipment mistake in show generally
Continuity mistake: In the episode "Malice in the Palace", Larry drops a hot dog after plating them, and never notices. After setting the cat up with a hot dog, the one on the floor, along with the small amount of water, has disappeared.