Second, don't assume you can use an essential oil for flavoring anything you're going to eat unless it's either food grade (usually labeled and more diluted to prevent injury), has been inspected by the FDA (these will have a nutrition label somewhere), or you know the oils are 100% pure with no additives and you know how to appropriately dilute them to make them edible. If there is no FDA label, there is a good chance that the oil is not 100% what it says it is - it most likely has some additives that are probably best not to consume. For these oils in particular, I personally would not consume them, despite the fact that the labels say they are 100% "insert oil here". The fact that the label specifically says "for external use only" helps that decision :P
An essential oil is a concentrated hydrophobic liquid containing volatile (defined as "the tendency of a substance to vaporize") aroma compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetherolea, or simply as the oil of the plant from which they were extracted, such as oil of clove. An essential oil is "essential" in the sense that it contains the "essence of" the plant's fragrance—the characteristic fragrance of the plant from which it is derived. The term essential used here does not mean indispensable as with the terms essential amino acid or essential fatty acid which are so called since they are nutritionally required by a given living organism. In contrast to fatty oils, essential oils typically evaporate completely without leaving a stain or residue.