bob squash, n. — Green’s Dictionary of Slang

bob squash n.

[rhy. sl.]

1. a wash.

1972		Dodson & Saczek Dict. of Cockney Rhy. Sl.
1992		R. Puxley Cockney Rabbit.

2. a public convenience; thus work the bob, for a pickpocket to rob jackets and coats that have been hung up while people wash their hands.

1992