Green’s Dictionary of Slang

of children, to scramble for a handful of small change tossed to them, typically at a wedding.

1981		(con. c.1920) P. Crosbie Your Dinner’s Poured Out! 104: He was ‘Grushying’ money in the shape of sixpences, threepenny bits, pennies, ha’pennies and farthings.
1994		(con. 1930s) K.C. Kearns Dublin Tenement Life 47: And the groom would throw out a few coppers in a brown bag to the kids, Ha’pennies and pennies. Oh, Yeah, that was called the ‘grushie’.
1999		(con. 1900s) R. Doyle A Star Called Henry (2000) 9: There were kids outside, a scabby-headed mob, waiting for the grushie.