I'm not planning on using it too often. Just trying to find a quick way of removing mineral deposits.
I'm amazed on a window cleaning forum of thousands of members I seem to be the only one with this problem Same goes for lead staining, there seems little interest and even less cures.
I have come across cleaners who carry a bottle of Harpic in the van. Not sure what they use it for.
I've tried Harpic on glass from cement stains after some bricks walls had been re-grouted. Didn't touch it. We don't have hard water in our area so very really come across limescale on windows. If we did then Harpic may help on those, but I don't know.
I also had a glass conservatory roof to clean once that was stained with lead stains from the lead flashing above it. Spent ages trying various chemicals which made no visible difference. Customer wasn't impressed with my efforts and ended up losing money on that clean. (6 years on the roof is still stained with lead deposits.)
Now I don't bother. Yes, I would love to make every customer be in awe with the results of every clean, but I know now there are some things I can't clean satisfactorily. In fact one conservatory cleaning company advised that the solution to the lead staining/deposits on the conservatory roof was to replace the flashing and the glass.
If you didn't do that block of flats, would it impact on your income? As an established window cleaner, I would doubt it. I have too much work atm so if I come across an issue like this I tell the owners right away that this is beyond my scope of expertise.
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