The visible marks on the window glass are [description, with an ordinary photo if available], but I cannot tell which surface they are on. Can you identify them as being on the inside or outside surface, or is an on-site check needed? If they may be between the panes, please state whether this is outside ordinary cleaning. Which surfaces can you clean, which are excluded and which remain unconfirmed? I am not requesting glass dismantling or do-it-yourself work at height, and do not assume the marks can all be removed.
