Do a rough job of cleaning (5)
I believe the answer is:
scour
'do' is the definition.
(thesaurus)
'a rough job of cleaning' is the wordplay.
I cannot really see how this works, but
'of' could be 'o' and 'o' is found in the answer.
The remaining letters 'scur' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for scour that I've seen before include "Clean by rubbing with an abrasive" , "Clean by hard rubbing" , "Scrub clean" , "flush out" , "Attack with brush" .)