Activated charcoal is charcoal (a form of carbon) that has been treated with oxygen to open up millions of tiny pores between the carbon atoms. The use of special manufacturing techniques results in highly porous charcoals that have surface areas of 300-2,000 square metres per gram. These charcoals are widely used to adsorb odorous, colored, infectious and toxic substances from gases or liquids. When a material adsorbs something, it attaches to it by chemical attraction. The huge surface area of activated charcoal gives it countless bonding sites. When passing next to the carbon surface, many things attach and are trapped, while other chemicals and coumpounds are not attracted to carbon at all. Once all of the bonding sites are filled, activated charcoal no longer has any detoxifying effect. An example of how activated charcoal is used in daily life is in water purification filters.