A method for removing contaminants in a fuel cell comprises: supplying a hydrogen-based fuel to the anode; supplying a first oxidant to the cathode, wherein the first oxidant comprises at least some sulfur dioxide; drawing a primary load from the fuel cell stack while supplying the hydrogen-based fuel to the anode and the air to the cathode; shutting down the fuel cell when a voltage of the fuel cell is equal to or less than a threshold voltage at which sulfur crosses over from the cathode to the anode, wherein shutting down the fuel cell comprises: performing at least one oxidant starvation while drawing the primary load, removing the primary load after performing the at least one oxidant starvation, and bringing the anode to a high potential after removing the primary load; and thereafter, restarting the fuel cell.