made of metallic material and destined for the melting process 1 are brought together as a group components such as instrument panels 8 seats 9 linings 10 floor mats 11 and bumpers 12 are brought together as another group electric equipment 13 audio units 14 and meters 15 that are destined for the renovation process 3 are brought together as yet another group see fig1 in the second step the connecting parts that connect various parts to the vehicle body or to each other are constructed so as to be easily broken apart the easily separable structure designing step for instance the instrument panel 8 may be adapted to retain the audio unit 14 the control unit for the air conditioner and various meters 15 each provided with a lock device using a suitable snap fit arrangement that can be readily released the instrument panel 8 may be adapted to be readily detached from the vehicle body 7 by using a lock mechanism that uses an eccentric cam the floor mat 11 may be provided with a readily breakable part extending through the parts joining the seat 9 to the vehicle body 7 so that the floor mat 11 may be removed from the vehicle body 7 by tearing apart the readily breakable parts without requiring the seats to be removed the electric components are adapted for flat harnesses and quick couplers so that the cables may be detached without any difficulty in the third step various components are given with a modular structure using a common member for supporting a plurality of components so that the various components may be removed.