This is something that is all over Pinterest and the Internet. Our towels recently have had a slight mildew-sour smell despite regular washing, so I gave this a whirl. First I washed my towels using bleach simply because mine had makeup, dirt and maybe some hair dye on them. If your towels are not white or don’t need bleaching just skip this step. The second step I used hot water white setting and one cup vinegar. Third step, wash again with a hot water setting and one half cup baking soda. Then dry. You need to have time enough to do all three washes in a row and obviously not when you will be needing hot water for showers. The towels came out soft and smell free! I have read on some sites that it helps with absorbency but our towels didn’t have this problem. Enjoy fresh towels!