Etch rates of hexatriacontane (HTC) as high as similar to 10 mg s(-1) m(-2) in late O(2) post-discharge are obtained at 333 K where no significant UV nor VUV irradiation occurs. Introducing N(2) in the gas mixture helps control the ratio of O/O(2) densities, which is shown to play a key role in the functionalization or etching of the HTC. The oxygen atoms are required for any further modification of the HTC because they initiate the formation of the radical chains by abstraction of one hydrogen. O((3)P) atoms do not contribute directly to break the alkane chain close to room temperature but they can functionalise it. O(2) is the important reactive species for the etching because of the role played by the peroxide groups on the scission of the hydrocarbon chains.