To remove sweat stains from colored clothing, soak the item in a mixture of cold water and white vinegar for between 20 and 30 minutes. Then, run cold water over the soiled area, and gently rub the area with your fingers to loosen the stain. Then, wash the clothing like you normally would — in a load with like colors.
I use Oxyclean, let them soak in the washer of like clothing for about 30 min, then launder as usual.
Angela, to properly clean any state you need to identify which you have. For bodily oil‘s use some cool water and shampoo. Scrub and rinse well. Bleach will not help you and will yellow the armpits. You may need an enzyme cleaner or stain remover if the shampoo doesn’t work. Let it soak If the first time of scrubbing and wetting doesn’t work.
Good ideas from other contributors. It helps if you can soak asap. Dried sweat is harder to get out.
try dawn and hydrogen peroxide and scrub in. for whites only
If the fabric allows, I put hot water in my biggest pot, add oxiclean, bring it to a boil and let it sit overnight. I do this /w clean dingy or stained items and I am amazed at the brown water that is there in the morning. (Remember these items were 'clean') Drain and wash as normal. This works great for old linens that have yellowed from storage.
Biz bleach is the best 2nd is Borax 20 mule