I go hiking in places that have funky birds (I live in Brazil, one thing we have a lot of is funky birds) and collect their fallen feathers, and I also worked at a
shelter for abandoned parrots, so I have accumulated a decent amount of feathers.
First, be warned- there are bugs that eat feathers, so keep an eye on your
art project. I have some fancy parrot feathers I stashed away and opened up the bag to find what looked like the mess after pantry bugs eat your beans or rice. I don't know how to repel them without toxic gick.
I usually find my feathers on the beach, so I want to get the salt and sand (and who knows what else) off, so I usually wash them in very dilute soapy
water (dish
soap). That's it. If I were going to use them near my face I'd be concerned about bacterial contamination and maybe use boiling water, but I don't. Once your feathers are dry you sort of "comb" them with your fingers (just like a bird preening) and the feather fibers will fall into place.