We have white uPVC windows and front and back doors.
They get this layer of grime on, that you cant really see until you're up close. Its like a grey film and then if you run your finger through it you can really see. It's also surprisingly hard to clean. It sort of rubs around but doesn't really come off.
I'm baffled - does this happen to anyone else? Is it a uPVC thing?
We are 2 people living in a one bed flat, so hardly high traffic everyday.