Checking the labels on the feather ones, it said 'Do not wash, do not dry clean' - Oh, well too late now.
pillows are really cheap to buy now. I occasionally put them on a delicate machine wash, then (if sunny) hang them outside for initial dry, then give a long half-heat tumble
it is important to get them fully dry to prevent rot
any that are no longer fit for use get binned or passed to cat rescue for bedding.