My new home is in Florida and when the windows were installed, a plastic film that comes stuck to the windows from the manufacturer was left on to protect the windows from paint, stucco and other construction materials. Now I am trying to peel this film off and I guess the sun and rain have strengthened the adhesive and it is impossible to take off. I have tried a putty knife and all kinds of oils and other adhesive removers. Do you have any other ideas? Please help!