Hi mate, ive just bought this incredible stuff called ProShine, it has Carbanau wax in it, you dont need to wash your car, just spray, rub in, then buff up, it cleans birds s**t, tar marks, insect splodges etc etc, have a wee look at www.netparts.co.uk and have a read for yourself, i was a bit sceptical but having tried lots of diffetent wax's/polishes over the years i thought i'd give it a try, it does exactly what it says on the tin. you can use this stuff on windows, plastic, alloys etc.
I know i sound like a sales rep for the company but it's the best stuff i've ever used and it takes no time to do your car, i done my whole car, including windows inside and out, plus wheels in 45 mins.
Tommy