Now that his window was all spotless, Mo extended his area of focus out by just a few feet. There were loads of people in the room cleaning with him, so it didn't make sense for him to run off willy-nilly and get in the way of people. Better that he stay here and make THIS spot as perfect as possible.

At some point or another, water had obviously leaked through this window, leaving rivulets of something green and disgusting on the stonework below the window. Mo spent a long time trying to identify shapes in the gross before finally pointing his wand at it. "Scourgify," he muttered, giving a small grin as the green disappeared and clean masonry appeared beneath. And people complained about cleaning.