The special effect of Burgess Meredith
creating a flame to light his cigar merely by snapping his fingers was accomplished by having two electric wires attached to a battery running up Meredith's coat and concealed on his fingers. Meredith held his fingers in a can of ice water until they were numb, and then a crew member put lighter fluid on his fingers. Bringing the wires together created a spark that ignited the fluid so he could light the cigar. See more
When Mr. Smith is driving the car, three different shots of the speedometer show the car racing, but the odometer never moves. (Though I suppose one could argue the odometer might have been broken.) See more
Exit the infernal machine, and with it his satanic majesty, Lucifer, prince of darkness - otherwise known as Mr. Smith. He's gone, but not for good; that wouldn't be like him - he's gone for bad. And he might be back, with another ticket = to The Twilight Zone.