The softness, warmth, comfort, and hypoallergenic properties of down comforters may be worth a little extra effort when it comes to cleaning them. A cover should be kept on your down comforter to protect it from dust, dirt and body oils, shaking it out once a week to keep the down evenly distributed. Air out your down comforter occasionally to keep it fresh, and take it to be professionally laundered every three to five years if you choose not to launder it yourself.
If you do choose to wash your down comforter yourself, spot clean it prior to washing. Your down comforter should be laundered in cold water only, using a detergent that has a degreaser so that oils will be removed. Squeeze any excess water out of the comforter gently, and dry the comforter on a low-heat setting, adding a tennis ball to the dryer to keep the down moving as it dries. Finally, during the times of year when down comforters are not in use, they should be stored in a dry, well-ventilated area to prevent mildew.