I apologize, this is not the most interesting post, but I have an issue with a very stubborn greasy film on my GTI windscreen, which I cannot remove, despite my best efforts. It is worse in the dark, when it's raining and facing oncoming headlights. I have tried "shaving" with a blade, use microfibre cloths, have used glass cleaner (such as Autoglym Fast Glass), don't use a wash leather and clean with a sponge which I only use for the windscreen. I have tried new wiper blades too. This all helps a little, but won't remove the film.
As part of my daily commute includes using the motorway, I understand this "film" may be unburnt diesel vapour. Has anyone experienced this problem, and, if so, could you recommend:
1. An effective glass cleaning product which will remove this film, and
2. A strong (and again effective) additive for the screen wash that can "cut through" this?
I have tried VW/Audi additive but although better than, say, the Halfords concentrate, is still doesn't remove this film.
Thanks in advance