Although aluminium and steel have been well recycled for many years, the development of new materials and new automotive designs resulting in unfavourable material associations raises the question of metal scrap quality. A new approach is required in order to integrate the limits of the shredding and dismantling processes regarding metal scrap quality into design. The purpose of this paper is to propose a new methodology to guide material choices during design. This methodology defines the minimum data and the interactions between design and end-of-life (EOL) material constants. The results such as the metal association matrix and the identification of process limits help to avoid recycling problems, which are taken into account in design requirements in order to improve metal scrap quality. This paper is based on a study concerning metal scrap quality and shredding and dismantling performances during end-of-life vehicle (ELV) treatment. (c) 2007 Published by Elsevier Ltd.