I have a Metal building to clean that was a repair shop with a loft over the office. They wanted to clean the walls over the office which is not too bad but no spraying water all over as it will run down between the 2x8 roof boards into the office ceiling insulation. They wanted it cleaned by hand like with a sponge and bucket of water or cleaner. The walls are mostly dusty and some years of grime but nothing like grease or mold as it is up high and you can stand on the boards and I am looking for the best way to do this. Maybe Pinesol and a sponge and bucket, or use a mop on the walls to keep the ceiling dry? The building is a metal building with rollup doors (3 on one side and one on the other side). I will use a housewash mix for those doors and walls but above the office I am not sure. Any suggestions? Thanks.