Feathers are way more durable than you think. I wash my feathers in the bath tub, a 5 gallon bucket or the sink. use a mild detergent like dawn. i fill the tub with about 4 inches of water, adding the detergent to make a nice foamy bath. put the feathers in the mixture and agitate by hand. if there is a stubborn stain i add liquid detergent directly to the spot and rub it in with my fingers. This is a technique directly taken from taxidermists. I rinse the feathers in warm water to ensure all detergent has been removed. then shake the feathers out one by one and spread out in the bottom of the tub to dry. By the way, we have a spare bath that my wife never uses. If this doesn't restore their shape, then you can steam them. i do about 300 goose wing feathers a year with this technique and have never had to steam any.