I just had a nightmare of a house to do,was so stressed out,all the windows were covered in silicon and the remains of where the plasterer had been,i spent so much time on them,i took most of the silicon of with white spirits and window scraped every window but i still could not get everything of them no matter how hard i tried really frustrating.
I believe that some of the staining on the windows was hard water which in itself is hard work,the customer seemed happy enough afterwards biut i was left feeling really really discontent with the finish.
I explained to the customer that it would take maybe three washes over time to rid all the silicon and dirt which seemed happy enough with.
What do you do with this type of problem and how much time do you spend on them???