Abstract: In order to reduce the concentration of CO in the waste gas of coke oven batteries that are heated by lean gas, additional sealing is used for the brick-work of die regenerator separating walls of the coke oven battery, as well as a coke oven battery with a regenerator having brick-built separating walls, between ducts that carry lean gas and waste gas, in which one has arranged stainless steel sheets in front of the regenerator separating wall with, preferably, an intermediate layer that is located behind it that comprises ceramic fibers. In this regard, the stainless steel sheets, that overlap with one another in each case, are preferably held by rod-shaped tensioning device.