We have the same problem i am hearing it might not be your washer it could be the dryer. we seem to keep washing the clothes and not find any rust spots but as soon as we r not testing for rust they appear. Now going to wet the shirt and dry it 20 times and see if we notice the dryer causing the problem. If it is looks like time for a new dryer. If anyone has a solution i would love to know. Have used the rust stuff in the washer machine.