Abstract: A method and an apparatus for identification and separation of metal boxes or cans, said can (1) being placed in a motor controlled cradle (7), and said cradle with the can being rotated in a first direction (a) to a first position with a first, preferably low stepping frequency, and then being rotated or influenced for rotation (b) back in a second and opposite direction (starting point position) with a second, preferably high stepping frequency, the time of said return movement simultaneously being measured as a function of the moment of inertia caused by said can and wherein said can as a function of the measurement of time and possibly of additional measurement of the can length and metal type is thrown out (A;B) of the cradle (7) either because said cradle is rotated further in said second direction (c) or because said cradle is rotated back (d) in the first direction and past said first position. Before the can is placed in said cradle it may be scanned inductively (3) and/or capacitively (21).