3M Overspray Masking Liquid - 1 US Gallon

Used on house windows when painting the frames.

I used this to mask the brickwork and glass around wooden window frames before painting them. It actually worked really well with not a spot of paint on the glass.

I painted it on to the glass and walls before starting, let it dry and then painted the frames. Once the paint was dry I washed it off. It is quite watery, so be careful of runs, but it made masking heavily textured glass much easier.