My personal favorite for washing anything down is Atsko Sport Wash. No residue left behind, no optical brighteners, etc.

For those who fear using their top-load washers, consider using yours just as a tub. Fill with water, add Sport Wash or cleaner of your preference, swish, add the down article, soak 3-10 minutes, swish BY HAND, spin, rinse, hand-swish, spin, rinse again and spin. A lot more water will be removed by your washing machine than you can get out by hand. After spinning, I hang down articles on my clothesline, then tumble in my dryer without heat.