Small old coins? No sweat! In lake back of Narrabri (5)

I believe the answer is:

oboli

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'small old coins?' is the definition.
'oboli' can be an answer for 'coins?' (I have seen 'old coins' mean 'oboli' so perhaps 'coins' could also mean 'oboli'). I'm not certain of the 'small old' bit.

'no sweat in lake back of narrabri' is the wordplay.
'no' becomes 'O' (O resembles 0).
'sweat in' becomes 'bo' (body odour. I am not sure about the 'in' bit.).
'lake' becomes 'L' (geographical abbreviation).
'back of' indicates one should take the final letters.
The final letter of 'narrabri' is 'i'.
'o'+'bo'+'l'+'i'='OBOLI'

Can you help me to learn more?

(Other definitions for oboli that I've seen before include "Old bits" , "antique coins" , "old coins" .)

I've seen this clue in the Sydney Morning Herald.

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