Essential oils—especially potent ones like Thieves and citrus oils—can eat away at plastic and cause some deterioration. You definitely don’t want to put plastic residue in your body. We recommend using a glass or stainless steel water bottle when you add essential oils to your drinking water and using a glass spray bottle—like the one included in our Home Cleaning Kit—stainless steel bottle, or a chemical-resistant plastic bottle when using Thieves Household Cleaner.