Abstract: A washer for cleaning a disposable cuvette rotor, which has a plurality of anaylsis cuvettes interconnected to form a ring. A stator, on which the ring is positioned for rotation, includes jets that direct flows of cleaning fluid in both horizontal and vertical directions into each of the chambers of the individual cuvettes. The jets are oriented so that turbulent flows of fluid clean the interior walls of each of the various chambers in the cuvettes. As well, the jets that direct the horizontal flow are oriented so as to drive the cuvette rotor rapidly in a circular motion about the stator. A regulator controls both the duration and pressure of the cleaning fluid provided to the jets while a fluid-tight container assures safe and efficient collection of the used cleaning fluid. In an alternate version of the washer, drainage of the spent wash fluid from the cuvettes is enhanced by slightly raising the cuvettes from the stator during a portion, or all, of their rotational travel.