Wait until an extremely sunny day when there are little or no clouds in the sky. Direct sunlight helps eliminate the mildew odor more quickly.
Locate a place in your yard (if using a clothesline) or porch that gets direct sunlight for a long period of time during the day.
Create a mixture of very diluted 3 percent hydrogen peroxide and tap water. The Michigan State University website recommends mixing one part of the hydrogen peroxide with five parts tap water.
Paint or spread the solution over the mildew-covered portion of the clothes item with a brush or cloth.
Place the item on a hanger so that it's fully spread out. Use a clothespin to attach the piece to the bottom of the item if necessary.
Hang the item on the porch or clothesline as early as direct sunlight first hits that particular spot. Hang the clothes all day until the sunlight is gone.
Repeat the process the next day, if necessary, to remove any lingering odors.