My mum uses vinegar for everything, the latest of course is wrapping the Xmas ham in a cotton bag (it's actually my old library drawstring bag that she made in the 1960's) soaked in vinegar. Keeps the ham fresh for ages.....
Where Does Vinegar Come From?
Vinegar is made when fresh, naturally sweet cider is fermented into an alcoholic beverage (hard cider). Then it is fermented once again. The result is vinegar.
Nobody knows for sure when mankind first discovered this, but most likely vinegar has been around for thousands of years, when man began to ferment fruits to make wine.
Check out some of the uses for vinegar: http://www.vinegartips.com/Scripts/pageViewSec.asp?id=7