Ants communicate by natural scents called pheromones; when a forager finds food, other ants pick up the trail by detecting the pheromones with their antennae. Spraying your kitchen counters, floor, baseboards and walls with white vinegar is an effective way to disrupt this pheromone trail. Vinegar causes mass confusion among ants, because, besides masking the natural odors they use to navigate, it's just generally repulsive to them. Essential oils, especially peppermint, clove, lemon and tea tree oil, have similar effects, and they smell much better to humans. Drop a few drops of one or a combination of oils on a cotton swab, and wipe along the baseboards or anywhere else you see ants entering.