Yes Apple Cider Vinegar can break up and clear out mucus and it does work for me when I have mucus.
To use Apple Cider Vinegar to clear up mucus Add a tablespoon of the raw, unfiltered Apple Cider Vinegar with 'the mother' to a glass of water and drink it, repeating up to three times a day until the mucus clears up.
The Mother of the Apple Cider Vinegar is the bacteria added to the Apple Cider Vinegar and This bacteria is what is known as the "Mother", because it is the catalyst that gives rise to the Vinegar.