Lou gets thrown from the washing machine. But when he gets up from the table, his hair and clothes are completely dry.
In the scene where Lou is on top of the car garage roof, a seam in the sky cyclorama can clearly be seen, even in long shot, and shadows of trees are also reflected on the "sky."
When Wishy (Lou Costello) is hanging from the back bumper of the car, his feet disappear as he is trying to climb back up to the car.