The proper way to wash a duffel bag depends on the material and overall design. Those made of nylon, polyester, or canvas are sometimes machine-washable, but you'll want to be careful about laundering zippers, buckles, and handles. Like regular suitcases, rolling duffel bags with wheels and telescoping handles usually aren't machine-washable. Your best bet is to wipe down the interior with a mild cleaning solution or a disposable disinfecting cloth and spot-clean the exterior as needed. When in doubt, check the brand's recommended care instructions.