Metals, glass, building materials, clay ceramics and most plastics are made from limited raw materials. Much of the energy used to make them also comes from limited resources. Getting raw materials out of the Earth by quarrying and mining damages the environment.
Reducing the use of materials, reusing them and recycling them cuts the use of limited resources and energy sources. It also reduces waste and environmental impacts. People who buy and use products, the end users, play a big part in this.
Some products can be reused. A glass bottle can be washed and refilled. Glass bottles can also be crushed and melted to make different glass products. Other products cannot be reused, so they are recycled for a different use. Metals are recycled by melting and recasting, or by reforming into different products.
The amount of separation needed for recycling depends on the material and on the properties needed in the final product. For example, scrap steel can be added to iron from a blast furnace. This reduces the amount of iron that has to be extracted from iron ore.