I wash mine in the machine regularly. I let them half dry naturally then put them back on the furniture slightly damp and they are fine. I don't do mine that often but a friend washes her cream ones monthly and they still look fine.
Yep - I do it all the time and they come out good as new each time! They can take a while to dry inside though, so maybe make sure you can get them out in the fresh air (if it doesn't rain that is). I don't risk putting them in the dryer.