Treatments of the hexatriacontane at 330 K (HTC-C36H74) in late N-2-O-2 remote microwave plasmas under 400 Pa is presented in this work. Time evolutions of the mass of the HTC are reported as a function of the gas composition and correlation with the HTC compositions by chemical analyses is carried out. The nitrogen atoms alone have no significant effect on the hexatriacontane. On the contrary, oxygen late post-discharges can be as efficient as direct plasma treatments to etch the HTC. In N-2-O-2 post-discharges, grafting and etching occur during a single experiment. However, the role of the oxygen atoms seems to be strongly correlated with the functionalization of the HTC and not clearly with its etching. (c) 2005 Elsevier B.V. All rights reserved.