When the car makes a turn in the intersection, all the windows are up. In the next shot taken from the driver side of the car, the windows to the rear doors are open. Since the car has manual windows operated by crank handles, Bonnie and Billy would not have had time to roll them down all the way this quickly, which this system takes longer than with the more convenient power windows.
The car wash tunnel has windows in pairs of two in most shots. In the exterior shot of the car being sent into the tunnel, there appears to be three in a line.
When Bonnie and Billy's mom gets inside the car to comment on its cleanliness, in the shot where she mentions the interior, the roof is shown to be back up. Once the camera cuts to her children and she questions them about opening the roof, it is still open.
The car's gearshift changes position in between shots. If parked while the inside of the car is being vacuumed when the gearshift shown uses the automatic transmission form, it should be all the way tilted forward.
Throughout the episode, the car first appears in the form of a 2-door convertible, and then a 4-door convertible with the rear doors sans handles; and finally from the point of the roof opening all the way down and afterwards, it is a 4-door convertible with door handles on all doors.
The car wash shown in this episode uses a conveyorized system, but has an inaccurate sequence of cycles. Its cycles in order include: pre-washing, the use of rotating brushes, washing, and then drying. The correct order of cycles these conveyorized systems use in real life are: pre-wash, washing with rotating brushes, rinsing with rotating brushes, wax or polish, and then drying.
After Party forms a hot-air balloon over her head, she magically puts the car into gear without the engine running and there is no key in the ignition in order to send it into the car wash and is on leveled ground. This is not possible in real life. Cars can only shifted out of park with the key in the ignition and turned in the ON position regardless if the engine is running, but can only start if in park or neutral. The only time a car can move when not in park without the engine running is on a slope where they can only go downwards.
It is illegal for kids to ride through any car wash without being supervised by their parents or any adult guardian, due to safety reasons.
When the scene changes to the intersection near the end of this episode, the car with the kids and their mom is shown to run the stop sign while making a sharp right turn, while almost hitting the oncoming car from the left lane in which the street they enter is cross-traffic. This is illegal as cars are required to come to a complete stop when encountering a stop sign or a red light.
Conveyorized car washes do not stop cars at each cycle before moving on to the next. They go continuously while one side of a car's tires ride on the conveyor belt while the car's gear is put in neutral.
Right after P.C. snaps his fingers to release Puffball from the dustbin, the car wash with the car inside is missing the conveyor belt. When the scene changes back to inside the car wash when Bonnie and Billy attempt to put the roof back up before giving up, the conveyor belt is back.
In the shots where Bonnie and Billy's mom leaves the kids and later when the car wash attendant (supposedly) finishes the vacuuming job that both use the same background, the car's roof's rear window is much smaller than in other shots.
When Party and P.C. free Puffball from the vacuum she's trapped inside of, the vacuum is on the right-hand side of the arch that the lengthy hose wraps around to the pole on the other side and where she is spat out of the nozzle. When the three all head back into the car wash tunnel, they walk off-screen to the left instead of to the right.
After they leave the car wash, they run the stop sign while entering the busy intersection with cross-traffic. It is illegal for any driver to run a stop sign.
In one shot of the sequence when Puffball gets sucked into the vacuum until she ends up in the canister, the inside of the car shows the windows with the rear window dominating the entire area of the roof's rear.
In the final scene when the camera shows the driver side of the car before the trunk opens with the Popples sunbathing inside, the rear-entry door windows are rolled all the way down. This was not possible back in those times when this episode aired in 1986 for cars of this configuration, and only the front-entry door windows could roll all the way down while the rear-entry door windows could only be rolled halfway down. It wasn't until by the late 2000s that manufacturers started manufacturing cars of this configuration to have the rear doors' windows roll all the way down.
After Billy and Bonnie's mom steps out of the car so she can meet them on the other side later on, when the camera angle changes to show her walking off-screen, she closes her door before the sound of it is heard.
Puffball goes skiing through the pre-wash cycle and then loses grip of the rope right as she exits that cycle. Several seconds later, she is in the car when the overhead dryers blow away the suds in the process. It is unexplained how she climbed into the car from the point of the car entering the wash cycle.
At the car wash, the cars are lined up in the queue before they each have their turn getting vacuumed out from the inside and then going into the car wash tunnel once the vacuuming is done. Once the car Billy and Bonnie and the Popples ride in enters the car wash, the car that's next in line (a blue sedan) doesn't pull up - especially at the moment Party and P.C. free Puffball from the canister vacuum.
When the car wash attendant starts vacuuming the car, Putter notices the vacuum and asks the car wash attendant to lend him the vacuum to "clean up" Puffball - whom ends up getting sucked in instead. It is out of character for any of the Popples to communicate with adults when they typically keep their presence hidden from them instead.