Clean up many a work (3)
I believe the answer is:
mop
'clean up' is the definition.
(I've seen this in another clue)
'many a work' is the wordplay.
'many' becomes 'm' (Roman numeral for a thousand).
'a work' becomes 'op' (common abbreviation for 'opus').
'm'+'op'='MOP'
(Other definitions for mop that I've seen before include "Tangle of hair" , "Clean; mass of hair" , "Bundle of soft material at end of stick for cleaning" , "Floor cleaner" , "Polish" .)