Metals are perhaps the most energy-efficient materials we can reuse over and over again. Recycling aluminum saves 95% of the energy used to make the material from scratch. Recycling steel and tin cans saves 74% of the energy used to produce them. Recycling one aluminum can save enough energy to run a 100-watt bulb for 20 hours, a computer for three hours, or a TV for two hours. And Americans use a lot of metals — 100 million tin and steel cans every day and enough iron and steel to supply the nation’s automakers on a continuous basis.