There is interest in understanding the chemical mechanisms in order to improve approaches for reforming fuels and regenerating components in solid oxide fuel cells. Chemical and electrochemical oxidative removal of carbon from Ni-YSZ anodes is studied using a suite of experimental techniques. After carbon is deposited on the anodes during methane exposure, it is removed with a series of the oxidizing mixtures containing a fixed O₂ concentration and varying H₂ concentrations. The CO and CO₂ produced are monitored in real time using IR emission and mass spectrometry. Concurrently, near IR imaging of the anode is employed to monitor the surface temperature and electrochemistry to track the open circuit potential of the cell. The data demonstrate monotonically increasing amount of CO and decreasing amount of CO₂ with the increasing H₂ concentration. In addition, a control experiment of carbon removal with H₂O yields relative amounts of evolved CO and CO₂ close to those observed with the 1:2 O₂:H₂ mixture. The results implicate atomic O and -OH as primary chemical removal agents, the latter being effective at oxidizing carbon to CO and the former at oxidizing CO to CO₂. In a separate experiment, electrochemical removal of the pre-formed carbon via cell polarization indicates an efficient oxidation of electrochemically accessible carbon to CO and a slow oxidation of CO to CO₂. Addition of H₂ gas during the polarization removal experiments leads to electrochemical generation of water inside the anode, which further accelerates oxidation of carbon. Thus, the present work clarifies mechanisms of carbon removal from the anodes of SOFCs.