Spoils is the term used by Shadowhunters to refer to anything taken from a Downworlder as part of the punishment for a crime. Spoils were either claimed by the Shadowhunter who has been wronged; forfeited to the Clave and then either kept in the Clave's treasury, or granted to a Shadowhunter, or to a particular family. Apparently, a good portion of the riches of many old, wealthy Shadowhunter families originate from spoils.
The awarding of spoils were first mentioned in Clave records around 1400. Spoils was a popular form of punishment for Downworlder offenses until the signing of the First Accords which, although did not eliminate spoils completely, strongly restricted the severity of the punishment, and also provided that the punishment of taking spoils from Downworlders could be executed only as part of an official sentence at a trial performed by the Clave.
During the time when the prohibition of spoils were still just reforms, the proposals were opposed heavily by some Shadowhunter families, particularly those strongly dependent on spoils for their wealth and stood to lose quite a lot, argued that the rules restricting spoils would harm the Clave directly as the wealthier families tend to tithe a percentage of their spoils to the Clave.
Non-wealth-related spoils are collected by some as trophies, displaying prizes from their victims and sometimes justified as justice- and duty-driven, particularly by those with disdain towards Downworlders.
The Clave claims to have returned many of the spoils taken in the past hundred years, though according to Luke Garroway, it was an almost impossible feat. Those which haven't are placed on display in various Institutes, as historical curiosities, and by some as a cruel yet proud display of vanity. In the 1870s, Aloysius Starkweather had an entire room that displayed all his spoils in the York Institute. Apparently, an Institute in Germany was originally a spoil taken from vampires. As of 2007, the Institute was still being fought over.