Using vinegar on your yoga mat isn't always recommended. The acids can damage the material. However, when done correctly, wiping down your mat with white vinegar after a sweaty class can increase your grip before your next one. Mix just half a cup of vinegar with water, apply it to your mat, let it sit for a few minutes, then rinse with water. It also has antibacterial properties!
Be sure not to use apple cider vinegar, as it can be especially harmful to your mat.