I would also try airing it for several days. Fresh air and sunshine can do wonders for smells.
If it still smells you could try putting it in a bag with baking soda to see if that helps or soak it and then dry. I put my batting in the dryer and use the steamer to get wrinkles out. I've never had it start to come apart so a gentle wash would probably be fine as a last resort. You could always try a small piece and see what happens