My DH has a tendency to overheat very easily and as a result the underarms of his tshirts can be a bit pongy. I wash them using detergent and fabric conditioner on a 40 degree wash and when possible, I hang them outside. I've just done a load and the underarms are still whiffy. He uses deodorant and showers daily so I'm really looking for something I can do while washing them. Is there a super strong detergent I can use or should I wash them on 60? Advice please!!