The reality of global climate change has focused the attention of the aluminum industry and its customers on the carbon footprint of our products. There are considerable efforts underway to replace primary metal with recycled metal units in the production of wrought alloys. The inevitable constraint is that there be no degradation in the performance of the final wrought product. Strength, formability, corrosion resistance, and surface quality are a few examples of issues confronted when alloy composition limits are simply increased without regard to the metallurgical impacts on microstructure and properties. Some impurity limits for decades-old legacy alloys hinder flexibility in scrap sourcing. A more flexible approach is based on microstructure, using compositional algorithms. This paper will address the major alloy elements and impurities (Fe, Si, Cu, Mn, Mg, Cr, and Zn) encountered in 3xxx and 5xxx alloys used in packaging and industrial applications in North America.