For whatever it's worth, when using a jar trap I find that ACV attracts fruit flies, while gnats prefer red wine. Will a white vinegar trap work? No, it lacks the sweetness of apple cider vinegar. I ...

A jar fly trap is a solid option if you have a few ... Remove the cone and add a few splashes of apple cider vinegar or white vinegar to the jar, then add several drops of liquid dishwashing ...

While store-bought fly traps are more expensive ... If you choose to use apple cider vinegar as opposed to typical white vinegar, you'll add the benefit of a sweeter smell and thus find better results ...