My dad worked with a guy like that, years ago. They're both mechanics, so they're both going to get hot and sweaty. This guy stunk, he knew he stunk, but he didn't care. My dad would tell him he stunk, but he would just smile, showing his funk-covered teeth. When Christmas came around, my dad both the guy some soap, wash cloths, toothbrush, and toothpaste, and told him not to come in the next day if he didn't use it. He actually washed his stank ass, but, it didn't last long. He finally went to work somewhere else, but summers were really tough around there.
I'd advise getting your boss to tell her, in a nice way, that she stinks. If that doesn't work, the coworkers need to say something. You can only put up with crap for so long.