C W Window Cleaning always use purified water which basically means it is completely de-ionised and de-mineralised. Unlike normal water this water is brilliant at cleaning windows as the water can dissolve any small partials and substances. Where your regular water would dries up and leaves streaks on your windows, the pure water can not do this, it simply evaporates leaving no residue.
When used regularly, this technique can not fail. However, if your windows have previously been cleaned differently with a more traditional manor using water and detergent (or not at all) you can expect your windows to have a stubborn film/ residue that has built up, you wont necessarily be able to see this but it will cause your windows to attract more unwanted dirt.
Because of this, we provide a service of a minimum of 3 cleans. This is because it would take 2/3 cleans to completely dissolve and remove all dirt and chemicals on your windows. So bare this in mind after your first clean, by your 3rd, we guarantee the results will be perfect.
Then by sticking to this method you will find your windows are more likely to stay clean for longer as there is nothing for the dirt to stick to