Abstract: Apparatus for pickling metal sheet as it moves along a generally flat horizontal path, comprises elongated shallow and sequentially arranged electrolytic pickling and mixed acid pickling tanks each having input and output ends and through which metal sheet to be pickled is continuously fed along a linear, flat path through the use of support rolls underlying the metal sheet at spaced locations between the input and output ends of the tanks. Pickling liquid is maintained in each of the tanks at a given level above the support rolls, whereby the sheet material is immersed in the pickling liquid between the input and output ends of the corresponding tank. Each tank has guide rolls at the input and output ends thereof for guiding the sheet material therethrough, and the support rolls are driven at the speed of the sheet material to minimize the tension on the sheet as it is being pickled.