Why hand-washing may be safer for a backpack than machine washing
Check the bag's frame, coating and care label; hand-clean with mild soap where allowed, then air-dry out of direct sun.
A backpack is not necessarily machine-washable clothing. Osprey recommends gentle hand-cleaning with mild soap and a soft brush instead of machine washing most packs, followed by thorough air-drying away from direct sun. Wheeled travel packs and specialist models may have different restrictions.