We have a towel set from our wedding nearly 12 years ago that have become musty smelling over the years. Maybe they were left wet on the floor for a day by the kids, maybe they were left wet in the washing machine for a day by me... it happens. Most of these were starting to smell bad enough that I was starting to think about replacing them, but they're still in great shape.
I tried pouring a cup of white vinegar into the washing machine with no other detergents like the thousands of Internet sites say to do, but that didn't help. I tried pouring in Borax along with the detergent, and that didn't help. I tried washing them all on high temperature when usually I just do cold, and that didn't help either.
Finally I decided to just soak each towel in as much water as it took to cover it, plus about 16 oz of apple cider vinegar. Soaked each towel individually for about 2 hours, then washed them together in detergent on high temp. And it finally worked! The towels smell normal again. Now I just need to wash the rest of the set.
February 14, 2019 at 11:51AM