Make an Air Freshener; Poke holes in the lid and fill with baking soda and essential oils. great for the auto also just make sure it does not tip over.
Make your own diffuser oil. Mix 3/4 cup mineral oil, 1/4 cup vodka, 1/2 cup essential oil. You can order the diffuser sticks on Amazon, 100 for $8.00 Very Cool, and fairly cheap.