Background being relatively inexpensive capable of being thermally processed rigid easy to process on high-speed lines readily recyclable total barrier to gas and light an important means of delivering a shelf-stable product - Food cans: three-piece construction (Figure 5.1).Background being relatively inexpensive capable of being thermally processed rigid easy to process on high-speed lines readily recyclable total barrier to gas and light an important means of delivering a shelf-stable product - Food cans: three-piece construction (Figure 5.1)