It's not like a mousepad, at least the type I've used.
Well when I used it I had two different ways of washing it. I would handwash it in the tub with either anti bacterial dishing washing soap or hand washing soap scrub it in good then rinse it out a bunch of times then hang it up to dry. When I was feeling lazy I would throw it in the washing machine. When I did this I would literally put a pinch of detergent (nothing like bleach, clorox, etc) then I would put it through the rinse cycle 3-4 times, then hang it up to drive.
I find it easier to clean it out side using a hose instead of using the washing machine. (mostly becasue my mom wont let me put it in the washing machine)
I've just started washing mine as well. Didn't use any detergant and only cold water on the longer cycle. I then hung it up on our drying rack, which only took about half an hour. Looks nice!
When we used it we would use a steam cleaner on it with no detergent, and occasionally throw it in the washer with one of the "everything free" detergents.
I wash my reptile carpet in the washing machine too and then I let it dry really well but I always have a clean new reptile carpet until the other one drys.