Make an All-Purpose Insect Repellent lemongrass or citronella oil, and 1 tbsp apple cider vinegar. 1 cup isopropyl alcohol, 1 cup water, ½ tsp. catnip oil. 1 cup alcohol or witch hazel and 10-20 drops of essential oils such as lemongrass, peppermint, or lemon eucalyptus.