Assuming that Charon formed in the outer Solar System, we expect it to have formed with an atmosphere consisting of CH₄ and other gases supported by volatile ice deposits (i.e., solid materials on the surface having atmospherically significant vapor pressures at Charon's temperature). The large obliquity of Pluto and Charon implies that volatile ices which originally existed on the surface at higher latitudes have been transported to latitudes below 32°. However, seasonally transient polar caps are possible when an atmosphere is present. Charon appears to have lost its atmosphere and surface volatiles. Owing to the lack of heating sufficient to cause widespread melting and separation of the lighter and heavier nonvolatile materials, Charon's outer layers probably retain their primordial mix of nonvolatiles. Therefore, spectroscopically determined relative abundances for Charon's surface should be representative for Charon's total mass (even if deep differentiation has occured) and thus may hold the key to understanding Charon's origin. The study of Charon's exposed nonvolatile ices (water ice, clathrate hydrates, any NH₃ hydrate, and other surface materials with atmospherically insignificant vapor pressures at Charon's temperature) may distinguish whether the Pluto-Charon system condensed densed directly out of the solar nebula or whether it condensed out of a protoplanetary nebula, as would be the case if these bodies originally formed as satellites of another planet.