In this paper the reverse Wagner/Whitin's dynamic production planning and inventory control model and some of its extensions are studied. In such reverse (product recovery) models, used products arrive to be stored and to be remanufactured at minimum cost. For the reverse model with given demand the zero-inventory-property of optimal solutions is proved, the corresponding Wagner/Whitin algorithm is presented and the stability of optimal solutions is discussed for the case of a large quantity of low cost used products. Furthermore, the model of the alternate application of remanufacturing and manufacturing processes is analyzed. Again, for the case of a large quantity of low cost used products the zero-inventory-property is proved, the Wagner/Whitin algorithm is applied to determine the periods in which used products are remanufactured or new products are produced, and the stability of Silver/Meal solutions for this model is sketched.