Window screens will often accumulate mildew, if kept in a damp environment and not cleaned for a long time. This powdery fungi has an unpleasant odor, and can cause numerous health problems, including allergic reactions in some people. Removing mildew as soon as you notice it is imperative. Fortunately, cleaning mildew off of a screen is a simple process, requiring nothing more than a good scrub with a cleansing solution.
Things You'll Need
Mix 9 parts water to 1 part bleach, together with a tablespoon of liquid detergent. Fill the spray bottle with the solution.
Remove the screen from the window and lay it on a tarp outdoors.
Spray the screen with the garden hose to begin the cleaning process. Spray the wet screen with the bleach solution and allow it to soak for five to 10 minutes.
Scrub the screen with the toothbrush, focusing on those specific areas that have visible mildew growing on them. Scrub hard enough to remove all mildew, but not so hard that you damage the screen.
Wipe the screen down with the sponge to brush away any loose bits of mildew remaining. Spray the screen once more with the garden hose, lifting it up to rinse both sides.
Shake the screen to remove any excess water. Let it fully dry in the sun before reinstalling.