A novel procedure for the preparation of electrochromic WO[subscript 3] films from readily available materials is presented. It is based on the electrochemical preparation of potassium tungstate from tungsten filaments of incandescent light bulbs in a potassium hydroxide solution. Tungstic acid is then produced by proton exchange using a super-absorbing polymer from a baby diaper. Simple air drying of the tungstic acid produces a tungsten(VI) oxide layer. On the surface of a copper foil or coupon or of a conducting glass, an electrochromic bleached (colorless)-to-colored (blue) transition of this oxide layer is easily observed by applying an external potential with a common power source in an electrochemical cell where the Cu (or the conducting glass) electrode is the cathode and a Pb electrode is the anode. This experiment can be performed in 2-3 h and is suitable for an applied inorganic chemistry or electrochemistry lab course. (Contains 2 figures.)