[john63.]

cleaned large house today took twice as long as it should of.
house had been rendered and windows were covered got some of it off anyone recommend anything
im trad.

[james nicholson]

brand new scraper blades and special clean price

[p1w1]

i would recommend brand new scraper blades and then plenty of soapy water and scrape in 1 direction only (forward) then wipe clean and repeat  do not scrape forwards and backwards as you will more then likely scratch the glass. I would also HIGHLY recommend that you get the customer to sign a scratched glass waiver and explain to them although you will do your very best to remove it you cant guarantee there may be small or faint scratches left. And of course price well.
paul

[pure tech]

I havn't used it but Titan Cement Off is designed for this.
I also think phosphoric acid dissolves/softens morter etc.

[Smudger]

brand new scraper blades and special clean price

+1

[robertphil]

soap up the window as much as you can so it flows down as you scrape ,carrying away grit