of material. The recycling of composite materials is more challenging than metal alloys because the industry has yet to develop methods to reuse the individual components that make up the material. A large portion of the composite materials become waste as aircraft are retired and disassembled. Recycling process The recycling process must ensure that there are low amounts of metal impurities within recycled aircraft components. As recycled components need to meet required specifications when implemented into other aircraft, recycled components (particularly metal alloys) must be organized properly to secure successful processing. First, an aircraft is transported to an aircraft-recycling center where it is disassembled. Desert conditions are ideal for storage because low humidity is required to maintain the condition of the aircraft. The aircraft is drained of fuel, washed to remove corrosive salt, and lubricated Explosive devices from the evacuation slides are removed, air ducts are sealed, and a protective layer of paint is applied. Non-metal components with no recycling value are discarded and the major areas of the aircraft are dismantled. Alloy components are organized based on their metallurgical composition, and then integrated as desired into alloying new metals. Alloying involves the gathering of scrap metal with different properties to be re-melted together to make a single homogenous alloy. The majority of alloys used in aircraft are either 2xxx (Al-Cu-Mn) or 7xxx (Al-Zn-Mg) series steels. When secondary alloying elements are found in excess of 10% within a steel alloy, the properties of the steel are especially valuable for recycling into aircraft use. Oftentimes, different alloys are implemented into different components of the aircraft which allows for clearer steel separation. Components such as landing gears, tail sections, flaps, wings, and fuselages are composed primarily of either 2xxx or 7xxx series steels, and are separated upon aircraft deconstruction. Seats can be worth up to $5000 and an aircraft landing gear can be sold for upwards of $1M. Cables, batteries and other electronic waste are fed into the conventional recycling chains. As plastic interior components often contain flame retardant chemicals, they are not recyclable. Even though recycled metal does not fulfill very high alloy specifications for properties such as toughness, recycled component metal can still be integrated into melting stock: a stock of different metals which are then melted together. Before recycled metal is introduced into metal stocks for alloying, additional processing is sometimes required for contaminant removal. Elemental residue is a