For a variety of reasons involving moisture, towels often have a strong musty smell, even after they have been washed with high-performance cleansers.
The odor comes from bacteria: it is the same principle as for mold on walls, except that in a towel, the bacteria stink.
How to kill bacteria and odors at the same time?
Add 1 cup of vinegar and 1 cup of baking sodato the washing water, without any detergent or softener.
Wash towels in warm water. [pub]
Then, they must be washed 2at atime, with very hot water and your usual detergent.
Dry them in the machine with a sheet of fabric softener.
With these 2 washes, your towels will no longer smell musty, I promise!