Turn the TV on and off very slowly to generate slow pulses high voltage, and this can run the motor continuously. The pop bottle motor always turns in the same direction regardless of polarity. The bottle motor works best on DC, but it will run on AC high voltage, like the slow AC from the TV screen as you turn it on and off. This method can work even though the sheet of aluminum foil touches only glass. The foil, glass, and the conductive phosphor coating inside the TV tube together act as a capacitor.
Capacitors act to block direct currents, but they allow alternating current to pass.
By turning the TV on and off, you are making the high voltage on the TV screen grow high and low, and the capacitor lets these changes in voltage go through.