Step 1. Check the care label
With the right supplies and equipment, most down comforters can be cleaned in a washing machine (down itself it washable; it’s the comforter casing that can shrink and stretch). But if the care instructions on yours say dry-clean only, take the item to a professional. Most cleaners will do the job for $25 or less—a small price to pay for peace of mind.
Step 2. Assess your equipment
The washing machine you use for regular loads of laundry might not be large enough to adequately clean a comforter. Head to your local laundromat and get in line for a commercial front-loading machine. (A too-small barrel could compress the down and distort your blanket.) You’ll also want to check that extra-large dryers are available.
Step 3. Machine wash on gentle
Spot treat your comforter with stain remover spray and place it in the washing machine with two tennis balls slipped and knotted inside a clean sock. Add a cap full of mild or all-natural detergent (too many suds could strip and damage the down) and set the machine on a gentle or delicate cycle, with cool or warm water. Run the comforter through two rinse cycles to ensure all the soap is removed.
Step 4. Dry and fluff
Place your comforter in the dryer along with the two tennis balls (they’ll help balance out the load and keep your blanket fluffy) and a large towel (it will stop the comforter case from getting too hot). Dry on the lowest heat possible, removing the blanket every half hour to plump it up. To know if the down is totally dry, hold the comforter up to the light. If you can see clumps of down through the fabric, dry the blanket bit longer. Improper drying could distort the down and allow mildew to grow. Stay patient—the process could take up to three hours.
Step 5. Consider a duvet cover
Go longer between washes by covering your comforter with a duvet. Wash the duvet once a week to remove body oil and dirt. To rejuvenate and re-fluff a comforter between cleanings, simply place it in the dryer once or twice a month.