Green’s Dictionary of Slang

1. crockery and glass sellers, their wares, their trade.

1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor I 324: The crockery-ware and glass-sellers (known in the street-trade as ‘crocks’). [Ibid.] II 44: It’s not such slavish work as the ‘crocks’.
1902		T.W. Connor [perf. Af Gibson] ‘All of a Sudden He Stopped’ 🎵 Smashing the crocks for a time was her boast, / Now sliding down bannisters pleases her most .
1909		(ref. to 1880) J. Ware Passing Eng. of the Victorian Era 98/2: Crocks (Art jargon, 1880). Ornamental china. This term came in when, from 1870 to 1880, the porcelain mania raged, and huge sums were given for even poor specimens of china.

2. crockery, esp. in context of washing it up.

1907

Gem 16 Mar. 15: ‘All my crocks!’ hooted Porker.