Inspect the down pillow cover to make sure there aren't any rips or tears before you wash it. Set your washing machine to the "delicate" cycle. Place two down pillows, or a pillow and a small blanket, into the washing machine at one time to balance the load.
Add gentle laundry soap, which will clean and deodorize the down. After the washing machine completes one cycle, rinse the load an extra time to remove all detergent from the feathers.
Transfer the pillows to a dryer, along with at least one pair of clean tennis shoes, to keep the down fluffy. Add a scented fabric softener sheet to the load, if you desire.
Dry the pillows for one to two hours, or until they are thoroughly dry. Take the pillows out of the dryer several times in the cycle, and fluff them by hand to ensure they are drying evenly. Place the dry pillows in direct sunlight to prevent mold and mildew growth, which can give down a bad odor.