What to do? what to do? gotta make special trip back because it wasn’t good enough the first time. need to get paid have to finish… please advise away
How old are the stains?
6 months- 1 yr old
Someone just gave me phosphoric acid cleaner but i’ve never had to clean frames like this before. He said it might work.
I use a phosphoric acid solution to clean CCU windows and frames where there are mortar/stucco/concrete splashes.
I spread at the top with a squeeze bottle and spread with a hogshair brush. The bristles won’t trap loosened debris, which can cause scratches if dragged across the glass with a washer sleeve. Hydrate the area below the window. The phosphoric acid loosens the bond between sand and mortar.
I’ve never used it on just stains, but it might work.
