I was bored and was just looking around at different sites and found Gardiners are doing a protection add on for brushes i am sure it wont be any good to lots of people but it looks great if it works as i live in the country and a big part of my round is old houses with old windows and frames .
http://www.gardinerpolesystems.co.uk/acatalog/info-BRUSH-BUMPER.html
http://www.gardinerpolesystems.co.uk/acatalog/info-BRUSH-BUMPER.html