From Halopedia, the Halo wiki
Salvaging is a practice, prominently exercised after the Human-Covenant War, in which individuals or employees of private organizations attempt to recover lost civilian, UNSC, or Covenant technology and/or military assets.
Fetching is a specific type of salvaging in which individuals known as fetchers, who often work for private organizations, travel to former battlefields and recover slipspace drives from derelict vessels in order to sell them to the UNSC.
Aiming to avoid the costs of their own salvagers and scouts, the UNSC employed the use of fetchers in addition to buying at clearinghouse auctions, where salvagers could sell their scavanged scrap to any group willing to buy it. By January 2557, the UNSC had stationed a buyer in New Tyne on the planet Venezia, the home of Nor Fel's clearing house. Additionally, the UNSC has established the UNSC Salvage Directive, which governs the procedures surrounding the salvaging of UNSC vessels by independent parties.
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