Vinegar jars are used to sour someone's life.
Luckymojo has a wonderful article on vinegar jars and other types of bottle/jar spells:
With a vinegar jar, you want to place cursing ingredients (Chili/Red Pepper, Cayenne, Black pepper, nails, etc) in the jar, any personal concerns of who you're doing it for (Hair, fingernail clippings, menstrual blood, etc). If you don't have those items, use a picture as well as a name paper. Fill it about 1/4 of the way with vinegar.
Once sealed, you can burn a black candle on top, or you can shake it daily, verbally cursing whoever it is you're doing work on. When it is not being shaken, keep it wrapped in a thick black cloth, or a couple of black towels and store away somewhere safe until the next day.