Green’s Dictionary of Slang

church n.2

[play on christen v. (1)]

(US Und.) a place where the identity of stolen jewellery is altered.

[Aus]Sydney Sl. Dict. 10/2: I got the thimble to church and fenced it for three cooter, and four deaners for lush for the cross coves and their blowers. We went to the gaff that night and tried to work, but spied a keen-eyed cop marking, and we guyed.
[US]Monteleone Criminal Sl. (rev. edn).

In compounds

churchman (n.)

(UK Und.) one who alters the identity of stolen jewellery.

[UK]G.M.W. Reynolds Mysteries of London III 66/1: Tim sent the yack to church and christen but the churchman came to it through poll, as Tim’s shaler had slummed on him a sprat and an alderman last week.