White vinegar against yellow armpit stains and stink.

Ever had the problem of not being able to raise your arms in public because you had these annoying yellow stains in your perfectly white shirt? Or that you put on your freshly washed and dried clothes and as soon as you get a little sweaty they start smelling like sh*t? 
Here's your very simple solution: White vinegar.
For the yellow armpit stains and stink: Replace your washing product with a cup of vinegar and just run your cycle like you normally would do. When it's really bad, you might want to bathe your clothes in a bath of white vinegar for the night and than wash them.

After a summer festival my Aubade bra kept giving off this terrible smell, even after I washed it. I bathed it in white vinegar for the night and washed it afterwards. Now it smells perfectly fine again.