Non-ferrous metals (either pure or alloyed) contain no iron. They may be light (aluminum), are good conductors of electricity (copper) and are corrosion resistant (brass). Some are common (lead, tin), others are very valuable (gold, silver, platinum and nickel). Some are quite scarce (mercury, titanium)
These metals tend to be more valuable than ferrous metals are are usually re-cycled. Metal waste from industry is collected. Used items are cleaned sorted and melted for re-manufacture.