Hi Harry, there is no such thing as self cleaning glass, even Pilkington self cleaning glass while it does self clean to a certain extent with the reaction of the Sun and Rain it still needs to be cleaned with wfp or trad to maintain it properly, you can get nano based coatings for glass which will leave a superhydrophobic finish on the surface and when the rain/water beads down the glass it takes a certain amount of soils with it which does help in keeping the glass cleaner for longer and will help in making it easier to clean in the future, but again will need to be cleaned with wfp or trad to maintain the glass properly, many companies are good at hype/spin and clever marketing skills (just watch some of the Barry Scott adds on TV, Bang and the dirt is gone yeah right) need i say anymore. Tadgh