I've washed mine several times. Do you have a gentle/delicate cycle on your machine? That's what I use with warm water and a tiny bit of soap (charlies is what we use now). I have air dried it when short on time but it's better to hang to dry over the bathtub or similar.
I've washed mine several times too, like others said just use the delicate cycle and air dry (I believe it says on it or in the instruction manual not to put in the dryer). Mostly washed w/ just water, the one time DS was sick in it and it stunk horribly we used Tide.