I washed a house with vinyl siding, and it had a large enclosed patio FULL of glass windows. I went back after the cleaning and noticed the windows were FULL of spots and the lady was cleaning them. I felt as if I should have cleaned them but how do you do it without losing $$$ and without trying to make another sale at the job site. Before you say anything about water, I used their city water. This seems like it might occur regularly. I need some pro opinions. Thanks!