We have studied the effect of a wet-chemical cleaning procedure and a thermal hydrogen treatment on Si-terminated 6H–SiC(0001) and C-terminated 6H–SiC(0001̄) surfaces by photoelectron spectroscopy and low-energy electron diffraction (LEED). On SiC(0001), the different steps of the wet-chemical treatment result in oxygen-contaminated surfaces with a monolayer of Si+ due to hydroxyl groups. The first step of the wet-chemical treatment also produces Si4+ accompanied by a (3×3)R30° LEED pattern, indicating the presence of areas terminated by a silicate adlayer on the surface. Annealing of SiC(0001) and SiC(0001̄) surfaces in molecular hydrogen at temperatures around 1000°C removes surface oxygen and results in H-terminated surfaces with (1×1) periodicity, which are electronically and chemically passivated.