I moved into a “as is” house and i suspect that at one point they used privacy film on the windows. the film is no longer here but there is residual color scretched into the glass. Thought Icould clean it with OTC cleansers throughout the years i have used everything fron paint remover, goo gone etc. there is nothing to remove eith razor blades, its like it is imbedded into the glass. do i have only options to clean it?