A combine harvester (10) grain cleaner (43) comprises an in-use upper, relatively moveable framework supporting one or more grain sieves (17, 18, 19) and an in-use lower, relatively fixed framework (56, 57) supporting one or more clean grain sheets and/or tailings sheets (23, 46, 47), the or each said clean grain sheet and/or tailings sheets (23, 46, 47) being vibratory and connected to a vibrator (57, 58) that causes movement of grain thereon in a predetermined direction.