A boat cover with window film is also easy to clean.
How can I clean and impregnate a boat cover with window film?
You can clean a boat cover or tent with window film with Sprayhood & Tent Shampoo and Power Cleaner. And finally impregnate again with Sprayhood & Tent Protector.
It is not harmful if the shampoo, the Power Cleaner or the impregnating agent gets on the foil. You can even use the shampoo to clean windows. Do you still see dried drops of impregnation after impregnation? You can simply remove these with a cloth and Ultramar Plstic Window Cleaner & Protector.