How to Make Homemade Bug Spray: Fill spray bottle-glass preferably-(I used 8 ounce) 1/2 full with distilled or boiled water. Add witch hazel to fill almost to the top. Add approximately 30 drops of essential oils to desired scent. Hint: The more oils you use, the stronger the spray will be. My personal favorite mix is: Purification, Lavender, and Eucalyptus… it works great and smells good too!