Green’s Dictionary of Slang

one who ‘passes round the hat’, e.g. after a busker’s performance.

1936		W.A. Gape Half a Million Tramps 33: She sang on the streets, but as she had no ‘bottler’ she did not collect as much as she would if someone was helping her.
1989		in G. Tremlett Little Legs 171: I’m a great bottler, one of the best.
1997		Share Slanguage.