steel cans are made of steels & steel is always magnetic ->  steel cans are magnetic  aluminum cans are made of aluminums & aluminum is always nonmagnetic ->  aluminum cans are nonmagnetic  steel cans are magnetic & aluminum cans are nonmagnetic ->  a mixture of steel cans and aluminum cans is an example of a mixture of magetic and nonmagnetic material  a mixture of steel cans and aluminum cans is an example of a mixture of magetic and nonmagnetic material & magnet can be used for separating a magnetic material from a mixture of a magnetic and nonmagnetic material -> a magnet can be used to separate steel cans and aluminum cans