According to Elle Magazine, to remove the smell in stinky jeans, it first needs to be determined what is causing the smell in the jeans. Rawr Denim explains that denim does not need to be washed every time it is worn.
Jeans can start to smell if worn several times without washing. To avoid wear and shrinkage, denim should not be washed every time. However, bacteria from the skin can transfer to the material causing it to stink. Jeans can also start to stink if there was a spill of some sort of liquid or solid on them.
White vinegar can be added to the washing machine while the jeans are in it: This acts as a deodorizer. Vinegar works as a neutralizer in the fabric to diminish smells.
A strong detergent or cleaning agent, such as OxiClean or Borax, can be added to a container filled with hot water. Soak the jeans in this solution first, and wash then in the washing machine.
Elle Magazine suggests that one way to lower the amount of bacteria that accumulates on the jeans, and causes them to smell, is to freeze the jeans. Bacteria thrive in warm temperatures. Freezing the jeans kills the bacteria, eliminating the chance for the bacteria to cause the jeans to start to stink. Once the jeans return to a warmer temperature, bacteria can return. However, the jeans can be frozen often without causing wear on them, proving an alternative to washing them more often.