Be aware that quite a few of them are cotton and cotton can shrink. The last one I washed was not quite big enough to put back on. I had to add a small piece of fabric on one end. (It works fine.)
Why wash it when you can buy a new mickey mouse one. Just kidding, this is the budget board afterall. I did just see a Mickey Mouse Ironing pad on sale @ disneyshopping.com . I think it was 8.99.
I have washed mine in the past and it came out okay, but it was harder to fit on the board. Maybe I shouldn't have dried it in the dryer.