This study analyses the metal recyclability from waste Printed Circuit Boards (PCBs) with three material recycling quoting approaches: Material Recycling Efficiency (MRE), Resource Recovery Efficiency (RRE), and Quotes for Environmentally Weighted Recyclability (QWERTY). The results indicate that MRE is likely inapplicable to quoting the metal recyclability of waste PCBs because it makes the recycling of any metal is equal to each other (e.g. recycling of 1 kg of gold is as important as recycling of 1 kg of iron). RRE and QWERTY can overcome the poor yardstick of MRE because they concern not only the weight of recycled materials but also the contribution of recycled materials to the natural resource conservation and the environmental impact reduction, respectively. These two approaches, however, report an extremely different result, that makes the target stakeholders get confused with which material recycled. From the findings of the aforementioned analysis, this study proposes the Model for Evaluating Metal Recycling Efficiency from Complex Scraps (MEMRECS) as a new approach to quotes the metal recycling performance. MEMRECS allows a trade-offs between three criteria: mass, environmental impacts and natural resources conservation, hence it can provide the result in a sustainable sound manner. MEMRECS clearly models and enhances the role of natural resources conservation aspect rather than QWERTY does.