The best way to rid the ants from your houseplants are by repotting them in new soil. Avoid transferring any ants to the new potting media. Keep newly repotted plants quarantined in an ant-free location until you are certain the plant is "ant free". Make sure that there is no honeydew on your plants. Honeydew is secreted by scale, mealybug, or aphids, which feed on some houseplants.