Many batteries are thrown away in regular waste after they have been used. Battery recycling is a name of the process of separately collecting such batteries so that they can be disposed of properly. Batteries contain metals such as lead, copper or zinc. In the form that is used in the batteries, these metals are very harmful to the environment - most are toxic. Collecting the batteries allows the extraction of some of the metals, which can then be re-used, not thrown away. The parts that cannot be extracted or re-used are disposed of in a way that is less harmful to the environment. For this reason, many countries have rules that say that a given percentage of all batteries must be re-cycled. 