Machine-wash. Machine-wash your down jacket on a gentle cycle at 30 degrees °C. If it's available, select the 'extra rinse' option. Use a down-specific soap or detergent, like Granger's Downwash. Skip the spin cycle. It's better for your jacket to drip dry and/or use a tumble dryer.
Preseason is a great time to wash your down jacket—to bring it back to full. The new Nikwax Down Wash Direct is specially formulated to clean down garments .
