Polish Conservative, outwardly disagreeable (5)
I believe the answer is:
scour
'polish' is the definition.
(I've seen this in another clue)
'conservative outwardly disagreeable' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'outwardly' means one lot of letters goes inside another (some letters go outside others).
'disagreeable' becomes 'sour' (I've seen this in another clue).
'c' going into 'sour' is 'SCOUR'.
(Other definitions for scour that I've seen before include "Clean by hard rubbing" , "scrub and scrape" , "Clean - scout" , "search in detail" , "Clean abrasively" .)