Ooh, we can see why this would be a problem. The most likely source of the odor is that you're waiting too long to remove your towels from the washing machine before putting them into the dryer. Because towels are so heavy, it doesn't take very long for them to sour when they're wet. Another cause could be that you're just not using enough detergent. Try using a bit more (especially if you have hard water) to really get the towels clean. Also, wash your towels in hot water with a bleach (obviously, a color-safe version if they're not white). This will help rid of bacteria and mildew that cause odors. An extra dryer sheet or two also will help give your towels a fresher scent.
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