Fluff left in denim has degraded (9)
I believe the answer is:
mishandle
'fluff' is the definition.
(I know that fluff can be written as mishandle)
'left in denim has degraded' is the wordplay.
I cannot really understand how this works, but
'left' could be 'hand' (left hand) and 'hand' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for mishandle that I've seen before include "Fumble" , "Maltreat" , "Wrongly manage" , "Bungle" , "Badly judge" .)