Clean axe (5)
I believe the answer is:
scrub
This clue is a double definition.
'clean' is the first definition.
(scrub can mean to clean)
'axe' is the second definition.
(I've seen this before)
(Other definitions for scrub that I've seen before include "Rough country area" , "Get rid of" , "clean-up" , "Take out - clean" , "Rub hard with a brush" .)