Synthetic fabrics have a surface that bacteria attach to really easily. It's one reason gym clothes pick up smells that no amount of washing can get rid of. The

Synthetic fabrics have a surface that bacteria attach to really easily. It's one reason gym clothes pick up smells that no amount of washing can get rid of. The only fabric I've ever used which doesn't do this is merino, but it's hard to find merino clothes other than base layer. Merino is so antimicrobial that if you hang dry merino training clothes that are soaked in sweat they will smell fresh.