Clean it well, but gently, in the water.Shouldn't need to let it soak.Rinse numerous times until completely clean of any soap residue. I use compressed air, at a distance to dry the feathers. A hair dryer works as well, but no high heat.
Many excellent taxidermists do use gas to degrease or displace water with birds. Manyexcellent taxidermists do not. I personally don't think it's worth the risk or health hazards.