If I understand you correctly, you still have spots (dust?) on your negatives even though you have washed them 30 minutes and this is a real problem because it is 35mm. I doubt it is dust as you surmise but I guess it could be. You might try using a film cleaner like that made by Edwal. I have had mixed success using it and you might want to try a small area first. It this doesn't do it and someone else can't help then I guess you will just have to get good at spotting--it happens to all of us.(posted 9013 days ago)