Recommended Use : Because essential oils are highly concentrated they need to be used with care. Apply them by the drop. The general rule is to dilute them with carrier oils such as jojoba sweet almond or grape seed when used on the skin. Wyndmere uses 15 ml (1/2 ounce) bottles into which they put 10 ml (1/3 ounce) of liquid. The bottles will be 2/3 s full. Wyndmere takes every precaution to make sure that 10 ml (1/3 ounce) is being delivered into every bottle.