Ollie falls off the roof into a pond, gets out and he's dry.
The first time he climbs the ladder, the back of his suspenders come undone and then they're fastened.
At the end of the film just before the car is squashed between two trams Ollie is in the front with Stan but after the car is squashed he's on the back seat with his wife.
When Ollie falls off the ladder and lands in front of the bus, his formerly soiled shirt is suddenly clean.
When Stan and Ollie are sitting in the lily pond after the chimney has fallen on them, you can see one of the fake bricks floating in the water.
Visible square-shaped protective plating under Hardy's pants when they are on fire.
As Stan tries to start the engine he glances over at Oliver, and the faintest of a smile come on his face.