Green’s Dictionary of Slang

(UK tramp) a penny or any copper coin, usu. in pl.

1910		‘Doss Chiderdoss’ ‘Telling ’Em Something’ Sporting Times 3 Dec. 2/2: They’ll bite it all gay / If ’e’s down on the blokes with the ‘clods’.
1921		N&Q 12 Ser. IX 345: Clods. Money (usually copper coins).
1933		‘George Orwell’ Down and Out in Complete Works I (1986) 176: These (omitting the ones that everyone knows) are some of the cant words now used in London: [...] Clods – coppers.
1941		G. Kersh They Die with Their Boots Clean 29: Barker can refer to ‘Forty tosheroons’ or ‘Six o’ Clods’.
1959		F. Norman in Encounter n.d. in Norman’s London (1969) 61: penny – Clod.
1968		J. Healy Death of an Irish Town 8: You remember Jimmy Foley, the baker, who was always good for ‘the odd clod’ to make up fourpence.
1981		(con. 1920s) P. Crosbie Your Dinner’s Poured Out! 220: clod a penny.