I'd recommend either borax or baking or washing soda added to your wash,and use hot water. It sounds like a mildew problem. Bleach would also work, but if the washcloths are colors they'll fade, and the other things are non-toxic. A pre-soak with it might be good, or an extra rinse. Do you live in an area with hard water? Both the borax and baking soda soften the water, helping to remove whatever is on there.

I think the solution is to keep them as dry as possible. Hang to dry after using (on a towel bar?), then wash as soon as possible and dry quickly and comnpletely. Hanging in the sun (a natural deodorizer) would be a great choice!

I agree with all the above tips: Rinse well and hang to dry after using, and use borax along with your laundry detergent if in a hard water area. Use vinegar in the softener dispenser and they come out really soft and fluffy without fabric softener.

According to my experience don't leave clothes in the washer for too long. When the cycle is done, immediately put them in the dryer. If I leave clothes in to long, they get a weird smell.

Thanks for all the advice! We don't have hard water, and we don't let clothes sit in the washer for too long. But, I leave a washcloth in my shower where they haven't been drying out, so I will now wring those out and hang them to dry elsewhere. I also just washed some towels yesterday using hot water (we always use cold) and noticed an instant improvement. The washcloths had no smell when they came out of the dryer! After we use up our Bounce sheets, we'll have to try the vinegar...

I hang wash out a lot. Love smell of sheets hung out on a nice breezy day.But had lady tell me I'm old fashion. But she complaining thought she was going to have her lights turned off.In winter I hang wash rags rung out on edge of laundry basket before I wash them.