Green’s Dictionary of Slang

a member of an underclass who espouse a hippie n.² (3) lifestyle, although modernized with more of a ‘punk’ edge; they adopt deliberately filthy clothing (thus their ‘crustiness’), live communally (often in squats) or on the streets, enjoy an excess of drink and drugs and generally set out to appal their less extreme peers; also as adj.

1993		Observer (London) 29 Aug. 5/8: [I]ts editors do not known what a slap-head is, have never tossed a coin to a crusty, and would not recognise a soap-dodger at a festival.
1994		N.Y. Mag. 27:21 23 May 33: Where the beatniks and hippies and punks once trod, there are now Crusties — young, mostly white kids hopping freight trains and squatting in abandoned buildings that lack running water for bathing, hence the name.
1998		I. Welsh Filth 167: It’s full of student and crusty trash on tight budgets.
1999		Guardian Guide 13–19 Nov. 29: Dreadlocked crusties, students and some of the city’s professional workers congregating side by side.
2003		N. Griffiths Stump 64: All aloof to them crusties around her, must be script day for em.
2009		Mail & Guardian (Johannesburg) 24 Sept. 🌐 I won’t be calling my kids Moondrop or Skypony or whatever the hell crusties call their children.
2012		J. Fagan Panopticon (2013) 14: Crusty reaches out to shake my hand. ‘Hello, Anais, I’m your support worker’.
2016		‘Chelsea Summers’ in http://www.racked.com 28 Dec. 🌐 They can both share the shredded aesthetic most reminiscent of a Salvation Army castoff worn by a dumpster-diving crustpunk.
2020		(con. 1991-94) W. Boyle City of Margins 101: ‘Crust punks?’ ‘They live in squats [...] Hop freight trains. Lots of homemade tats [...] and they dress crustie. All black, studded jackets, boots [...] dogs’.