Seller ultimately associated with Polish sock production? (6)
I believe the answer is:
shiner
'sock production?' is the definition.
(sock can mean a punch)
'seller ultimately associated with polish' is the wordplay.
'seller ultimately' becomes 'r' (I can't explain this - if you can you should give a lot more credence to this answer).
'associated with' is a charade indicator (letters next to each other).
'polish' becomes 'shine' (synonyms).
'r' put after 'shine' is 'SHINER'.
Can you help me to learn more?
(Other definitions for shiner that I've seen before include "It may result from punch" , "Star" , "Possible end of scrapping" , "A slangy black eye" , "injury to face?" .)