A study of chemical etching and chemo‐mechanical polishing of Hg0.8Cd0.2Te (MCT) with bromine‐methanol has been carried out. It was found that the etch rate could be controlled down to 0.1 nm/s when 0.001% of bromine‐methanol was used. Surface analysis using x‐ray photoelectron spectroscopy indicated that differential etching of the constituents and accumulation of elemental tellurium occurred even when only a few monolayers were etched from a stoichiometric MCT surface. The relative etch rates were determined to be Cd≫ Hg≳Te. Nevertheless, it was found that chemo‐mechanical polishing could produce smooth surfaces with no significant accumulation of elemental tellurium. The production of such surfaces, however, required a balance of chemical etching and mechanical lapping. Furthermore, quick quenching of chemical etching was o required after chemo‐mechanical polishing in order to prevent further surface degradation.