Finished my car with GWC after a wash on Monday. The car is ceramic coated so it was really just done to produce some beading. I rinsed off immediately as per the instructions. Got in the car this morning (not driven it since Monday) and noticed what look like white spots on the windscreen. The paintwork seems Ok as far as i can tell. I'm wondering if I haven't rinsed the screen properly and this is the result. Any thoughts - and suggestions as to how to fix ?