When a strip (2) of e.g. hot steel is rolled by a rolling or roughing mill, scale develops on the surface of the strip (2) which must be removed. The strip (2) is passed over a bending roller (5) which bends the strip (2) and causes cracks in the scale. Then water is injected (11) on to the strip (2) to wash the roller (5) to lift off the scale. Inertia then causes the water and scale to leave the surface of the strip (2) and pass to a collection means (12) whose water collecting surface (14) is out of contact with the strip (2) and on the opposite side of the bending roller (5) from the water injection (11). In this way the time of contact of the water with the strip can be kept short and the strip is not damaged by contact with the collection means (12). A further bending roller (6), water injection means (15), and collection means (16) may be provided to remove scale from the other side of the strip (2).