May be related to his technique (temperature, detergent dosing), especially when doing laundry "not here."

I would probably guess he needs to change his laundry habits. Ditch the cold water washes, ditch the cheap liquid detergents, and sort properly. Use little or zero fabric softener. Anything that touches flesh contains body soil and requires at least warm water to shift. Forget clothing labels, if they can touch your skin and stand the dryer on at least low heat, they can be washed in warm or hot. Choose a powdered detergent, preferably Tide or similar. If his clothes stink, his washer probably does too. Clean the machine before cleaning the clothes: Longest, hottest wash cycle, bleach, and rinse well. Still stinks?...Try it again. Leave the lid/door open when not in use. What you are smelling is bacteria and germs mixed with sweat that have now festered into a funk between the fibers of the laundry. It will take more than one wash to remove stink from laundry that has been washed and dried over and over again; bleaching any laundry that can take it will remove the smell quicker, AFTER they have been washed with detergent. Hanging all stinky, but laundered, wash in the direct sun for a day will also neutralize the smell. Hope this helps, and best of luck!! I am sure others will chime in, too! :)

Could be his house. I take he doesn't live with you just does laundry on occasion there. I have been in houses that smell musty before. Nothing to do with cleanliness of the house. Maybe just a ventilation problem. Then that smell eventually transfers to clothes, furniture, everything in the house. Just my thoughts but could be purely laundry related. If it doesn't bother him I wouldn't worry about it either.

OP you don't say but does you son have a washer if so what type? Also what detergent does he use and what water temp? Hard water?

If he is using a TL then clean out the fabric softener dispenser. That would be a good idea regardless what kind of a machine is used, but I know on my TL that fabric softener dispenser can hold onto anything that touches it.

I had the stomach flu recently. I put concentrated lysol disinfectant liquid in the wash and could smell that stuff weeks later. i couldn't figure out why since I had run bleach in the machine many times since. Well, somehow it got in the fabric softener dispenser. I cleaned it out and the smell was gone.

Jody, what did you use to clean out the FS dispenser, please?

I just used soap and water. I put the pull out dispenser in hot water and used a toothbrush to clean it out really well with dish soap. The part that stays in the washer, I used a cleaning brush and some Simple Green cleaner to clean it out. I then ran a large load with bleach to make sure everything got rinsed out well.

Add some Borax with the detergent. This will help sweeten the load.

^^^^^^

This. Stuff is a miracle worker for stuff like this :)

Thank you all! I am going to try Borax and also pick up some detergent for workout clothes.

If Borax fails, and I doubt it will, your next bet is some sudsy ammonia added to the wash bath or first rinse.

MRB

I agree with the Borax attempt. But I will say, I tried it on my husband's workout gear – – lots of synthetics – – and they really hold the musty odors. I had to move on to what I call "Larsi's Stink Bombs," which are Tide Odor Defense pods with Febreeze. Give the boy a big bag of them, and tell him to put one in EVERY load. Da bomb.