Vinegar does get rid of nits, or head lice eggs, but it does not get rid of adult head lice. It also gets rid of young lice that cannot yet lay eggs. This is because the acid contained in vinegar has the ability to kill germs.
The acid in vinegar is able to dissolve the outer skeleton of nits, which renders them unable to stick to the hair. They can then be combed out of hair with a nit comb.
White vinegar, red or white wine vinegar and apple cider vinegar are all effective at killing nits. Any of these types of vinegar should be applied close to the scalp, and allowed to sit for a few minutes. This enables the vinegar to kill the nits.