An elongated washer for cleaning the inside of slaughtered, eviscerated poultry, comprising a spraying element to which cleaning liquid can be fed, and radially projecting parts, running mainly in the lengthwise direction, being disposed near the spraying element, which parts are provided with sharp projections. Preferably, the sharp projections run in the lengthwise direction. The projecting parts are advantageously plate-shaped and the radial dimensions thereof, viewed in the lengthwise direction, decrease from a central part towards both ends. In a method for cleaning birds using the washer the spraying element and the projecting parts are inserted through an opening near the anus of the bird and are moved in the direction of and through the neck part.