I'm looking for a reliable cleaner to wash a wall in my living room after a repaint. The wall is about 4m wide and 2.5m high, with some light scuffs and pencil marks from a child. Please bring non-abrasive cleaning supplies suitable for painted plaster. I’d prefer a careful approach to avoid damaging the new paint finish. It’s a small job, but I want it done thoroughly so the wall looks fresh again. Flexible on timing, but ideally a morning appointment. Please include any preparation steps or products you plan to use in advance.