Gather ingredients and measure 16 ounces of white vinegar into a plastic container.
Add 15 drops -- approximately one teaspoon -- of essential oil. Add as much as one additional teaspoon of oil if the fragrance is too weak. Consider using lemon essential oil to remove unpleasant odors, eucalyptus to destroy mites or lavender to promote restful sleep.
Label the container and place it in a safe place out of children's reach.
For a normal-size load of laundry, place 1/2 cup softener and 1/2 cup water in the machine's fabric-softener dispenser, or add it at the beginning of the rinse cycle.
For softer clothes, mix 1/2 cup baking soda with 3 cups vinegar in a large bowl. Slowly add 1/2 cup baking soda in small amounts, because the mixture will initially bubble up as the soda dissolves. Wait several minutes before adding the softener mixture to a plastic container. Add essential oil and gently shake to mix.