While vinegar can kill flies, it doesn't do so in the way you might expect. Vinegar doesn't kill by poisoning ... If you're dealing with fruit flies, for instance, make sure to remove any fruits ...

The other day, I spent five minutes amid a circling halo of fruit flies, searching my hanging basket for the culprit. It turned out to be a rotting baby potato hidden amongst the fresh ones.

Homemade traps using apple cider vinegar, overripe fruit, wine, or beer can effectively catch and kill fruit flies. Lemons with cloves and essential oils like lavender, eucalyptus, and peppermint ...