To clean a screened-in porch, gather materials such as mild soap solution, vinegar, baking soda, and a soft brush. Remove loose debris with a broom or vacuum. Dilute mild soap in water and gently wipe down screens with a sponge or cloth. Remove stubborn stains with vinegar or baking soda. Rinse screens thoroughly and let them dry. For deep cleaning, consider using a commercial cleaner or a pressure washer if appropriate for the screen material. Ensure safety by wearing gloves, using proper equipment for high screens, and avoiding slippery surfaces.