I used white vinegar and put it in a pre soak cycle for a few hours. But again, I had nothing to lose. I would try the freezer first then the vinegar. not sure about the down but I googled. Got this

How do you get body odor out of a down jacket?White VinegarWhite vinegar is a powerful odor neutralizer and works wonders on underarm areas of fabrics. Fill your washing machine with water, then add 1/3 cup of white vinegar. Turn off the machine and let the garment soak for 20 minutes, then launder as usual.

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please come back and let me know if it works. Good luck! Oh I saw another one that suggested using a spray bottle vinegar and not wash it.