A wash bag is a small mesh bag that protects delicate clothes in the washing machine. To use a wash bag, fill it with your desired articles, seal it shut and toss it into the washer. A wash bag provides enough cushioning to defend delicate garments like silk shirts and wool sweaters from zipper snags and tears, while allowing water and detergent to pass through the mesh so your clothes are cleaned effectively. Wash bags are especially helpful for washing bras and other lingerie because they prevent straps from tangling around the agitator. Using a wash bag can help keep your clothes looking newer, longer.