Abstract: Selective volatilization and collection method includes providing a substance, for example, solid and/or liquid, in a contained system; providing thermal energy to the system and substance, and a current, i.e., directed mass flow, from external to the system, such that, substantially without boiling, nor disturbing the substance surface, at least one component of the substance is volatilized. Volatilized substance component(s) are gently swept away from remaining substance by the current and collected. Apparatus useful in the method includes a generally enclosed vessel for holding the substance; gaseous matter entry port, with its exit end above the substance; and exit/collection port with a feature for collection of volatilized substance. An entry port wand having a throttle, porous ball, director channel(s) or other feature for tempering and/or directing incoming gaseous matter, which supplies the current in the method, may be in the apparatus.