Green’s Dictionary of Slang

1. a fake subscription list carried by one who poses as an alms collector.

1842		Edinburgh Rev. July 482: The [begging] documents are accompanied by a sham subscription-book [which] they name a ‘delicate’.
1851		Lancaster Gaz. 5 Apr. 3/5: The gentlemen whose names are attached to the brief are entered into the book for handsome sums. [...] They call the brief a ‘slum,’ and the book, a ‘delicate’ [...] The man who worked the above ‘slum’ and ‘delicate’ had been a firelurker a great number of years.
1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.

2. a begging-letter.

1891

F.W. Carew Autobiog. of a Gipsey 419: Screeving ‘shams’ and ‘delicates’ for begging-letter imposters.