Yea, I remember years ago when my mum and dad owned a shop, bread man was a bit too lazy and decided to reverse into the the window once. Massive panes of glass they were.
Obviously worried that it might have been weakened they called out a glazier (I think thats what they called him), would have been easy money as the shop was a good un and it could easily afford the odd big expense. Instead the glazier said "safe as houses" and gave the window the biggest punch I have ever seen!!!
Cleaning em, well to be honest I think using a swivel squeegy and aplicator on a pole looks like a heck of a lot of fun and I would pay to have a go on a really big window, am I the only soft idiot that feels this?