Blow the film using electric hair drier and then tear it off.
Heating the film using electric hair drier will work. And you can wash the residual things with medicinal liquid . Generally gasoline and alcohol is okay. It will easier to tear it off after it's heated.
There are many ways. 1. If the film is not too big, you can apply some banana oil to it and then scrub it with cleaning ball. 2. Detergent used in textile industry will work (Bottled such detergent is called al). I've tried it. It really works well. 3. Use sulfuric acid. But you should mix it with water before use, otherwise the door will corrode. Immerge the door into the mixed sulfuric acid for a period of time and scrub it with cleaning ball.
