Polish company in revolutionary Russia (5)
I believe the answer is:
scour
'polish' is the definition.
(I've seen this in another clue)
'company in revolutionary russia' is the wordplay.
'company' becomes 'co' (abbreviation).
'in' means one lot of letters goes inside another.
'revolutionary russia' becomes 'sur' (I am not sure about this - if you are sure you should believe this answer much more).
'co' inserted inside 'sur' is 'SCOUR'.
Can you help me to learn more?
(Other definitions for scour that I've seen before include "search in detail" , "purge" , "Scrub hard" , "Rub hard or search thoroughly" , "Full" .)