I always have, but there are a few ideas to keep your pillows from loosing shape or getting lumpy... ideally the best method I think is in a front loaders that has a delicate or even hand wash cycle as they are much more gentle than the top loaders. But don't be dismayed, if you have a top loader there is a really great way to wash pillows: fill the machine and soak the pillows stop the machine from agitating unless you have an extremely gentle cycle. Soak for at least 15 minutes at a lukewarm temperature unless cold water wash is mentioned on the pillow tag. After soaking skip the agitation cycle and set it to spin on low speed for a brief time, then repeat with clean, cold rinse water( again skipping the agitation and using the spin of low for only as long as needed to remove excess water. If you can lay the pillow to air dry on a mesh netting in the heat of the sunshine, you'll find it helps to not only freshen and purify your pillow but it'll cut down on drying time, expect it to be damp for a day or two. This can also be done without using the washer by soaking in a bathtub or laundry basin too... but then you'd need to squeeze the pillow with a large absorbent towel. Just remember to avoid the friction, that's what turns a comfy pillow into a clumps of lumps. If your pillow concern is just the outer surface and not the fibre inside then simply wipe the outer fabric with a wet soapy cloth, rinse quickly and hang it on the line.