Small quantities of hard fat can be added to your household food bin, if you have a collection. Alternatively, solid or liquid fat can be taken to one of north London's reuse and recycling centres (RRC) . Once cooled, simply collect it in a plastic or glass bottle, and check which RRC to go to (they do not all accept fat). Once collected, the oil will be converted into high quality bio-fuel for the distribution and power-generation industries. Old cooking oil can also be composted at home but just make sure it's mixed well with paper or cardboard first.