i used to clean a pub, and it had a BIG mirror
went allaround the place, must have started at 10 ft high of the ground and been 10 ft high itself (if you get what i mean)
i had to pole it all, used to use pure water with a small dash of GG in it, mop it on, sqeegee it off, any marks would normally dry clear
the mirror was 30 years old aswell, so wasnt in the best of nick and had etched bits which were a right pain
some c****y guy took over and now doesnt haev them done by any1