Laundry ... Removing sweat odors

Any suggestions for removing sweat smell (not BO level, but definitely sweat) from the arm pits of t-shirts?  

I've washed them with other clothes, soaked them in vinegar...  

I have stopped wearing them because they never start clean. I'm ok smelling sweaty after working outside but I don't want to start out that way. Ironically, these aren't work t-shirts but nicer ones (probably why they are holding the odor). Still cotton blend though.

They are colored so it needs to be something that won't remove color and please not toxic. Don't want to replace one issue with another.

Brainstorming off the top of my head:

1. Sprinkle baking soda on the area and allowing to set a bit, before spraying vinegar and letting it foam?
2. Spray ammonia on it? (not necessarily non-toxic)
3. Wearing an undershirt to make a barrier between your skin and the nicer shirt?
4. Some people suggest crushing an aspirin and sprinkling on the affected area? (Never tried it.)
5. I've also seen people suggest an antiseptic mouthwash soak. (Wondering if rubbing alcohol might also work?)
6. Line drying in the sun to help the UV rays neutralize the odors?

Theater costumers use alcohol (rubbing or just vodka) to kill the bacteria that are causing the odor. I have found this to work pretty well on my office clothes,  Does not need to be a soak, just a god swipe on the inside of the armpit.

Sonja

My husband works hard and works with all kinds of fluids that smell BAD...I had a horrible time getting the smells out.  It took me awhile to find the right detergent.  I now use Mrs Meyers which is extremely gentle; but I turned the hot water heater up considerably. I suggest trying a hotter temperature water.  It worked for me.  I mean HOT..

My inclination would be a paste of baking soda, soap and water on the smelly areas and left to dry. Then wash as usual. Preferably hang out in the sun to dry. The alcohol seems like a good idea too.
I've heard some people suggest putting smelly clothes in the freezer or outside, depending on weather. The idea being that the cold kills the critters causing the smells. This seems to work for me when I hang wet clothes outside to dry in freezing temps.

Borax works wonders, essentially creating Hydrogen Peroxide when mixed with water, which helps soften water which allows other detergents to work better. The problem may be that you are washing in hard water which does not allow detergent to diffuse into water and makes them ineffective.

We finally had a small break in the rain where I got a couple hours of sunshine.

I got the underarms of each shirt wet and then rubbed them with Dr Bronner unscented bar soap and then added a bunch of baking soda/water paste. I hung them in the sun to dry. I then put them in a bag until laundry day. I washed them on hot with my usual unscented detergent.

It worked! There is a bit of odor left on one and I'll re-treat it but I'm very happy I can add these shirts back to my wardrobe.

Thank you all for your suggestions! I'm hoping the ones I didn't need will benefit someone else.