Green’s Dictionary of Slang

1. to lock up, to imprison.

1887		H. Caine Deemster Ch. xxxiii: Poor Mastha Dan had been [...] jiggered up in Peel Castle.
1925		H. Leverage ‘Dict. Und.’ in Flynn’s mag. cited in Partridge DU (1949).

2. to unlock.

1976

Sutton & Linn Where The Money Was (2004) 210: He was going to jigger the door in a way that would allow us to get in.