Left one in a posh suburb in Eastern Europe, really shining (6)

I believe the answer is:

polish

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'suburb in eastern europe really shining' is the definition.
I can't judge whether this defines the answer.

'left one in a posh' is the wordplay.
'left' becomes 'l' (common abbreviation).
'one' becomes 'i' (Roman numeral).
'in' indicates putting letters inside.
'l'+'i'='li'
'li' placed inside 'posh' is 'POLISH'.

Can you help me to learn more?

(Other definitions for polish that I've seen before include "Europeans" , "make things shiny" , "'Buff, burnish (6)'" , "Smooth or shine by rubbing" , "Shine up the nationality" .)

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

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