I have been using 303 Fabric Guard on the convertible top. The products repels water very well and last pretty long. However, the side window and the rear window show a filmy residue after a rain. The windshield is not really affected. The film is spotty and can be removed only with glass cleaner and with a lot of friction with a microfiber cloth. It appears that when the top gets wet, the runoff carries with it some components that foul the windows. Not sure if it's some kind of resin or silicone.
Do all water repellents for convertible tops cause similar residue?
Do all water repellents for convertible tops cause similar residue?