Abstract: The same baskets are used to dip successive batches of parts into a path of cleaning fluid or the like, and between dips the baskets are raised to a position in which rails on which the parts are held in the baskets connect with intermediate rail pieces to form a continuous track so that the contents of each basket can be advanced to the next basket (or to the unloading station in the case of the last basket) while a new batch of parts is loaded into the first basket. The transfer operation is performed by a rake mechanism. The advantage is obtained that when the baths of cleaning fluid are at different temperatures, heat is not wasted in warming up and cooling the baskets and, furthermore, cleaning fluid is not lost by being carried away by baskets moving through the system.