Hello, All. I've found the solution to cleaning those nasty yellow pit stains and ring-around-the-color discoloration on your well-worn white uniforms. It's called M-30, and I found it at a dollar store. The canister label says it is a petroleum based product and I'm guessing mechanics use it to clean their hands also. I practice traditional karate and I sweat quite a lot, so yellow stains was always a problem even though I take conscientious care of my uniforms. I do not machine dry my uniforms and I always wash them right after a workout. Over the years I've tried Shout, dishwashing liquid, bar soap, 409, bleach, color-safe bleach, Oxyclean, you name it. None of them really helped that much. But this M-30 works very well. I rubbed a generous amount onto my stained spots and let it sit for about half an hour before washing it in my machine as normal. Then I let it air dry overnight. Much of the yellow stains have faded away. It's not all gone, but I think I'll repeat this treatment a few more times and see how it goes. At the very least, I'll be able to continue to use some tops that were reaching the 'beyond embarrassment' stage, and this might be an effective preventive measure to keep the stains from ever appearing in the first place. Just wanted to pass the tip on. Your mileage may vary if you have machine dried your uniforms in the past and have 'set' in the stains already.