Cleaned my first conservatory roof yesterday. It was actually one of those orangery jobbies with large wooden beams very high end build. Was quite nervous as I’m a bit of a squeegee novice but decided from the outset not to squeegee it. What I did was cleaned the beams with soapy water to get rid of bug poo wipe dry and get rid of cobwebs etc. Then I misted the inside of the panes with pure water, then wiped that off with a damp unger microfibre cloth then buffed with a dry one. Results were excellent! Pros, very easy for the inexperienced and inexpensive, Cons, in my case non however it may not work so well on a greasy kitchen soiled ceiling.