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.
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: After Cynthia's mother drinks some of Granny's white-lightning tea, the teacup disappears from her hand between shots.
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: 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.
The Rass'lin' Clampetts - S6-E22
Other mistake: When Granny throws the Boston Strong Girl out of the ring at the end, you can tell that the Boston Strong Girl is jumping to get over the ropes.
Factual error: In the opening scene, the Clampetts are driving home from Malibu. From Malibu to Beverly Hills is east. But as they head home, the ocean is on their left, which means they are driving west.