[Londoner]

Painters can get stick on film like cling film to cover the glass when painting. Its very cheap, Toolstation sells it for £5 a 20m roll. item no 20527

The first point you should be making to the customer is that there is absolutely no reason why there should ever be paint (or cement) on the glass in the first place.

Its not your job to clean up after shoddy workmen

[H S and Son]

That would be a rare situation I think so best not to worry till it comes up....

Best way to avoid it is target areas where they are mainly upvc windows, we only used to do a few wooden windows and always made sure they were well maintained before starting....

Is this serious?