A series of fulleranes, namely C60H36, C70H38, C60H18 and a mixture of hydrogenated fullerenes composed by 77% C60Hx and 22% C70Hy, were dissolved in oleum (fuming sulfuric acid) in order to record the radical cation spectra of these molecules. Surprisingly, it was found that the fulleranes spectra in oleum corresponded to the radical cation spectra of pristine C-60 and C-70 fullerenes. Therefore, it was concluded that the fulleranes in a high ionizing and oxidizing medium such as oleum are dehydrogenated and oxidized to C-60(+center dot) and C-70(+center dot). The prolonged contact with oleum leads to multiple sulfonation of the radical cations.