Dirty commertial windows

Hi,

I start a big project, with a really dirty windows. The window cleans ones a year only. I need to pass each window 13 times. I use a different Gardiner brushes. No one work fast.

Somebody use a brush with a bronze wool? Like Window weapon from Reach It?

Is it work good?

13 times sounds extremely excessive. Maybe using some degreaser first could help? High flow is also useful. 3-4 times really should be the maximum cleans needed.

13 times, thats extreme. I would throw some hypo on it, leave it 10 mins, rinse it off, job done!

Wash them with high flow of tap water once, rinse with pure once. Job done, move on.