Your bed's duvet is not immune from dust, dirt and even crumbs, not to mention spills that can stain it. Wash your duvet either by hand, to remove small spots, or in your home's washing machine. The toughest part of cleaning a duvet is drying it. Use a dryer setting with cool air to keep your duvet from shrinking, or dry it on a clothesline or drying rack.
Check your duvet's label to determine if you can wash the bedding in your washing machine. If the label states "do not machine wash," immediately stop and take your duvet to a dry cleaner or other professional for cleaning.
Treat any stains on your duvet with a laundry pre-treatment or stain remover by working the solution into the bedding using a soft-bristle, nylon scrubbing brush in circular motion. Circular motion keeps stains from spreading and becoming larger.
Insert your duvet in your home's washing machine so that the bedding wraps loosely around the machine's drum. For front loaders, place the duvet in the washing machine by itself--it will move freely around the machine.
Set the washer's water setting to "High" to fill the machine to its highest water level. Add 1 capful of washing powder to your washing machine. Set the washer's cycle setting to "Gentle" or similar setting.
If your duvet is heavily soiled, apply a laundry pre-treatment or stain remover to the bedding and let the solution sit overnight before washing the duvet.