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Metallic parts manufactured by conventional machining and additive manufacturing techniques possess poor surface quality and require post-processing operations before their end-use. Many methods exist for the post-processing of parts with free-form surfaces. In this study, two of the most used polishing techniques, electrolytic polishing (EP) and plasma electrolytic polishing (PeP), were investigated to understand the morphology of the resultant surface after both techniques. Pilot experiments suggested that an aqueous solution of ammonium sulphate is the most effective electrolyte for both the polishing techniques in terms of the lowest achievable value of average surface roughness (R_a). A systematic investigation of the electrolyte concentration, applied voltage, and polishing time revealed an identical dependence on all these process parameters, including decrease and then an increase in R_a. A minimum …