Double glazing window film is a thin layer of plastic sheeting applied to windows to hold in heat during cold winter months. This film is needed only on older single pane windows since they allow the most heat loss. Several forms of double glazing film can be applied to windows, but the easiest to apply is cling film. Cling film sticks to the slick surface of the window without tape or adhesive.
Fill a spray bottle 3/4 full with water, and add 1 to 2 tsp. of dish soap. Close the spray bottle, and shake it gently to dissolve the soap.