My neice gave me this trick for smelly dish clothes. She is an engineer and said that some kind of bacteria gets on them and this is what creates that unpleasant smell.
Put the clothes in a large bowl of water with a good dosage of baking soda. Then microwave for 10-15 minutes on high. (You could probably boil them on the stove in a large enough pot too.)
Then run them through the regular wash to get any excess baking soda out. I tried this and it worked like a charm.