Green’s Dictionary of Slang

sloughed (up) adj.

[slough v.]

(UK/US Und.) imprisoned, locked up.

[UK]Leaves from Diary of Celebrated Burglar 21/1: You can’t ‘kid’ me to stand here all day ‘slinging’ my ‘pewter’ into your bloody box, even if you are ‘sloughed up’. [Ibid.] 45/1: As soon as the place is ‘sloughed up’ and the ‘blokes namased,’ strike for the coffee shop next door to the hotel.
Emporia Dly Repub. (KS) 28 Apr. 3/2: ‘Sneezed’ means arrested, while ‘sloughed’ is used in the same connection.
[US]F.P. Dunne Mr Dooley in Peace and War 126: He’d been sloughed up f’r wan thing or another.
[US]J. Flynt Tramping with Tramps 273: I’ve boozed around this town [...] on and off for the last seven years, and I’ve not been sloughed up yet.
[US]C. Connors Bowery Life [ebook] Just den wun uv de bundles wot wuz sloughed up dere—wid er peach uv er black eye an’ er t’ree-months thirst—butted in.
[US]D. Lowrie My Life in Prison 283: They kept me sloughed up until I went into court.
[US]C. Panzram Journal of Murder in Gaddis & Long (2002) 174: I was sloughed up in isolation for over 2 years.
[US]E. Booth Stealing Through Life 300: Try that chip. See if it’s sloughed.
[UK] (ref. to 1920s) L. Duncan Over the Wall 75: Only through moments of relaxation did we get sloughed when we had to fill our systems with several slugs of bug-juice.
[Aus] ‘Whisper All Aussie Dict.’ in Kings Cross Whisper (Sydney) xl 4/4: sloughed up: To be placed in a cell.
[US]M. Braly On the Yard (2002) 205: The captain had let him walk on some beefs where he should have been sloughed.
[NZ]G. Newbold Big Huey 106: Those of us on transfer were sloughed up in an underground section called the Well.
[Aus]B. Matthews Intractable [ebook] After his recapture they kept him sloughed up in maximum security.

In phrases

get oneself sloughed up (v.)

(US Und.) to be moved from the general prison population into protective solitary confinement.

[US]Goldin et al. DAUL 79/2: Get oneself sloughed up. (P) See Get oneself locked up.