Have you ever forgotten your laundry in the washing machine overnight during the hottest part of the year? Have you inadvertently left damp clothing in your car's trunk or at the bottom of your hamper? Or worse, have you left wet clothes hanging on a clothesline only to have it rain on them, keeping them wet overnight or for a couple of days? If so, you probably know how musty and sour your laundry can become. Such circumstances can produce a pretty funky stink, and could ruin your good clothing.
If you have encountered this, you probably have also noticed that simply washing (or re-washing) the clothing doesn't always make that sour smell go away. It seems to get into the very fabric itself. Having found myself in just such a situation before, I experimented with a strategy to rid my clothes of the stench for good. All it takes is a little bit of hydrogen peroxide, and a little attention.
Wash your stinky clothes as usual, detergent and all, but add to the load about a third of a cup of peroxide once the machine is filled with water (otherwise you risk bleaching part of your load). I have found this works best in hot water, and as for the amount of peroxide, you kind of have to play it by ear. Larger loads (or particularly offensive-smelling smaller loads) will require a bit more peroxide, but a third of a cup has done the trick for me.
After the wash, make sure you thoroughly dry your clothing, or else the same problem will likely come back. Once dry, smell the formerly-offending bits, and if they still stink, you can run another wash -- this time without the need for detergent -- with a generous amount of peroxide. Also try
using vinegar to fix it.
If this still doesn't work, then unfortunately it might be time for a new wardrobe.