The invention relates to a method of operating a strip casting machine for producing a metal strip, during which molten metal is continuously poured between two casting rolls (1, 2) that form a casting gap. Lateral seals (10) having sealing plates (11) are provided for laterally delimiting the casting gap, whereby the sealing plates (11) are placed or pressed with a preset placement or pressing force, whose magnitude can be set, against the end surfaces of the casting rolls (1, 2). The sealing plates (11) are, in repeatable stop-and-go steps, placed with a preset force and time against the end surfaces of the casting rolls (1, 2) and are held in the placing position for a preset time. This enables a distinct reduction in the wear of the sealing plates and of the casting roll end surfaces.