Generally, it is not recommended to store undiluted essential oils in plastic containers, as some constituents in certain essential oils can break down specific types of plastic at high concentrations. This may compromise the oil and may cause leakage. Essential oils that are diluted with a carrier oil, or are a small part of a cream, lotion, or soap recipe, however, can be safely stored in a high-grade plastic bottle or container (such as the ones we carry) for several months. For more information about the types of plastics our bottles and containers are made from and whether or not they are safe to use with essential oils, please see the following link: www.aromatools.com/pages/types-of-plastic.