We have been asked a lot is it safe to use plastic bottles and containers to hold essential oils. **Undiluted essential oils should not be stored in plastic containers. However since our plastic bottles and containers are made of PET, diluted essential oils can be stored in our plastic bottles and containers. **PET may also be an excellent alternative to glass for some products. It is less expensive than a comparable glass container, weighs less than glass, and recycles well. PET bottles and jars may be a good option for storing products containing essential oils. HDPE is a high density plastic that is stiff, has a good temperature resistance, and is a very good water vapor barrier. It is also UV resistant!