Many synthetic fiber T-shirts, sweatshirts and shorts are popular with athletes since they often contain technology that helps wick away sweat. While these clothes may wick away moisture, they also absorb odors and can be almost impossible to launder away the smells. The solution is a natural and easy one: Fill a sink with hot water and a few tablespoons of baking soda and white vinegar. Soak the clothes for several hours and launder as normal. The clothes will come out smelling fresh and clean.