What seems to work for me is to hold them over the steam and use the steam to blow the feathers back up. Usually I get the kettle whistling before I start. Annoys the family real good 😆 so I try to wait till nobody is around.
When I have done all I think is possible with the steam, then I hold the arrow shaft in my palms and spin the arrow as fast as I can a few times. Then lean the arrow against the wall somewhere to recover. I like to put it on the mantle over the fire so it gets good and dry. This seems to help to.
Hope this helps.