hi. I noticed that there was the odd scratch here and there on some windows that I have cleaned unsure weather they where there already or done by the pole. I rang up the supplier and spoke to them about this problem. They said that it's impossible for there bush heads to scratch glass, and that I have been doing everything right with the pole when It comes to cleaning the brush heads. I sock them every day in pure water over night to make sure there clean for my next day's work, and also clean them with washing up liquid once a week with hot water. After talking to them feeling better with them saying that it is impossible to scratch the glass with there poles. I went out to clean a house, I noticed when I was finished that one of the Windows very badly scratched and you can see in the picture below. They are at the top and come down 7 inches then stop all in a line, then some going across the glass from the window being rinsed. (supplier said keep brush on glass when doing the rinse). They where not there befor I'm very sure as I've been doing them 7 mouths now. I am now in contact with the suppliers again. Has any one ever had this problem, I know the bush it's self can't scratch the glass but can the dirt on it scratch the glass? And if so what can I do to stop this. I am now paranoid that this can happen again and I'm really starting to think that water fed pole is not such a grate idea. What do people think any help please?