Abstract: In an automatic machine for washing self-service meal trays, comprising a sucker (7) by which soiled trays (3) are picked up from a trolley (2) and set down on a conveyor extending through a wash-and-dry tunnel (5) and running out to a restacking trolley, a first improvement consists in the addition of a device (12) by means of which compressed air is blown at the tray (3a) to the end of removing any waste matter and ensuring that the sucker (7) can apply a firm grip. A second improvement lies in the adoption of a power driven, horizontally disposed conveyor belt (16) on which the trays remain stably positioned by virtue of their own weight, free of mechanical constrains, so that any size and shape of tray can be handled without alteration to the machine, and cleansed in its entirety. Once washed, the trays are cleared of rinsing water by a blast of cold air before being dried off with further jets of air.