First, try to dry them off as much as possible. You can use a hairdryer on the low setting. Just be sure to keep the hair dryer moving so you don't overheat the fabric. Once they're mostly dry, put them in a dryer on the low setting or hang them up to air dry. If they're still wet, you can put them in the freezer for a few hours. This will kill any bacteria that might be growing and prevent the down from clumping.