Washing outside windows requires either a pressure washer or a scrub brush extended on a stick. Some second and third-story windows are not as easily accessible and may require you to hire professionals to accomplish this task. If that is not the case, or you have several windows that are accessible, then proceed. 

Teaching your middle school child how to use a pressure washer and then expecting them to use it correctly when you’re not watching is quite a huge step in the relationship with your child. If you don’t feel like they can handle the responsibility, have them use a water hose with the sprayer nozzle. 

Most of the time, just spraying off the outside of a window gets it clean enough to move forward with the next step in using Windex and paper towels to finish the job. Sometimes when there is a lot of dirt and mineral buildup on the window, you may need to utilize an extended scrub brush and some dawn dish soap. Ensure your child understands that they need to rinse the window well. 

Start this task during the time of day when the sun is not shining directly on the windows. They could start on the west and south sides of the house in the morning and move to the north and east sides of the house in the afternoon.   

You can see how this activity would take up most of the day. But you could combine it with some outdoor water fun. Even bigger kids like the sprinklers and the slip-and-slide. That way, they have a reason to wear their bathing suit.