Green’s Dictionary of Slang

1. to imprison (for a long time).

1822		Westmorland Gaz. 4 May 1/5: The two of them valiantly tok to their heels, leaving the prisoner [...] unable to toddle —to be grabbed by the charleys and warehoused in the roundy-ken.
1881		Punch 12 Feb. 71: D’you want to get us both ‘ware-housed’?
1997		E. Little Another Day in Paradise 258: They’re gonna do their best to wash me up, warehouse my ass.

2. (UK society) to place in pawn.

1890–1904

Farmer & Henley Sl. and Its Analogues.

3. (US) to place an individual, usu. a mental patient, in a large and impersonal institution, i.e. to ‘put them away’; thus warehousing n.

1972

National Rev. 7 Dec. 1259: California has pioneered the concept of treating the mentally ill with an expanded system of community mental health programs. [This] shift from the ‘warehousing of the mentally ill’ in large state mental institutions has become a model for the nation.