Your glazing will be perfect but it may take two or three cleans to completely remove the built up dirt.
You will also notice that it will take longer for your glass to get dirty.
On the first clean our operator will concentrate on your frames. The aim is to remove as much of the dirt trapped in the seals of your uPVC as possible. You will notice a significant improvement in the overall look of your windows by the time this is completed.
It is not unusual for the pure water to keep absorbing the dirt after the window cleaner has left.
If this is the case, you may notice general spotting on the glazing when the water has evaporated. Dont panic, this is normal. If your uPVC has seen a number of winters, your seals would have accumulated a sizable amount of trapped dirt and dust. In some cases this process maybe repeated on the second clean once again depending on the age or location (i.e. main road) of your window frames.