1. Make up a solution of two gallons of warm water, a quarter-cup of ammonia and two tablespoons of liquid dishwashing liquid. Mix until foamy.2. Using a rough-textured sponge, like a sea sponge, suds up the screen, lathering heavily (figure A).
3. Lay an old towel on the ground.
4. Line one edge of the screen up with the towel and give the screen several sharp taps on the ground (figure B). The dirt and foam will fall off the screen onto the towel.
5. Rinse thoroughly and dry the screen before returning it to the window.