A catalytic depolymerization (a reversible polymerization) of 3D-polymerized C60 phases (including an ultrahard fullerite phase) takes place in the presence of sulfur under the conditions of a large plastic deformation at room temperature. The sulfur atoms remain in the samples of 3D C60 polymers after catalytic synthesis using carbon disulfide (CS2) as a catalyst (the presence of sulfur has a considerable impact on the 3D C60 polymerization by decreasing the polymerization pressure). Raman, infrared, and transmission electron microscope studies show that the depolymerized fullerite samples have a structure typical for dimers, 1D and 2D C60 polymers. The 3D C60 samples with some remaining sulfur can be quenched under ambient conditions if the samples have not undergone a large plastic deformation. There is no depolymerization for pure C60 3D-polymerized phases synthesized without a sulfur-based catalyst.