If you're looking to clean the outside surfaces of the windows on your house but can't remove your screens, there is one easy way to get rid of the dirt without too much tinkering. Clean exterior windows make your house look nicer and improve visibility from within, so it is recommended that you clean the inside and outside of your windows at least once a month.
Pour a couple of capfuls of liquid dishwashing soap into your spray bottle, then fill the rest of the bottle with water from the tap.
Shake the bottle well to mix the water and soap.
Rinse your exterior windows by spraying them through the screen with the water hose. This will remove most loose debris, such as leaves, bugs and spider webs.
Spray each window with your soap/water mixture until the entire outside surface of the glass is coated. Dishwashing liquid breaks down dirt and grease, so it is a perfect soak for window exteriors.
Wait for 10 minutes. Then rinse the soap off your windows with the hose. Your windows should be clean, and your screens will likely see some improvement as well.