How should I properly wash a down sleeping bag to ensure it stays clean and maintains its quality?

To properly wash a down sleeping bag, use a front-loading washing machine on a gentle cycle with a mild detergent specifically designed for down products. Avoid using fabric softeners or bleach. After washing, tumble dry on low heat with a few clean tennis balls to help fluff up the down. Make sure the sleeping bag is completely dry before storing to prevent mold and mildew.