In a method in which two anodes are operated alternately opposite each other as plasma discharge anodes and as cathodes for self-cleaning, and the cathodes of the plasma discharge are recurrently briefly reversed in polarity, and an arrangement comprising a cathode and a first and a second anode supplied with voltage by an H-bridge circuit, pole reversal of cathode voltage is effected by a pulse current supply, at least one anode is maintained at positive potential at all times and the other anode intermittently at negative potential during an etching time, and the H-bridge circuit is operationally connected to the pulse current supply, such that at least one anode is at positive potential at all times.