Continuity mistake: In many of the early episodes Miss Jane drives a 1962 Plymouth convertible, but gets out of a 1963 or 1964 Dodge.
The Clampetts Strike Oil - S1-E1
Continuity mistake: As Granny is standing in the bucket cooling her feet, she looks at the man on the table, and has her glasses on. A second later they're suddenly gone.
Granny Learns to Drive - S2-E33
Continuity mistake: When Granny drives across the front lawn, the truck doesn't leave marks. When the motorcycle cop leaves, the bike leaves a clear trail.
Continuity mistake: After Cynthia's mother drinks some of Granny's white-lightning tea, the teacup disappears from her hand between shots.
Continuity mistake: Mr. Brewster's hair is parted on the left in three scenes in Pearl's parlor and then is parted on the right in one close up. (00:06:28 - 00:06:49)
Continuity mistake: Granny is chasing after Jethro with the intention of paddling him. She runs into the mansion and her blouse changes color from blue to pink (or is it white?) and back to blue again in the same scene.