Remove your hypoallergenic comforter from the bed and place it in an extra-large capacity washing machine to accommodate for bulkiness and size.
Fill the washing machine with warm water and add three-fourths the normal amount of gentle wash laundry detergent. Run the comforter through one regular washing cycle.
Remove all traces of laundry detergent from the hypoallergenic down comforter by rinsing it twice. Add 1 cup of white vinegar to the second rinse cycle to soften and fluff the fabric while deodorizing it, too.
Place the hypoallergenic down comforter in an extra-large capacity dryer. Add three to four unused tennis balls to fluff the comforter and prevent the down from clumping.
Take the comforter out of the dryer every 45 minutes to rearrange it in the dryer, ensuring that all its areas get dry. Continue this process until your hypoallergenic down comforter is completely dry.