One may be bent on filing them (8)
I believe the answer is:
toenails
'filing them' is the definition.
I can't tell whether this definition defines the answer.
'one may be bent on' is the wordplay.
'may be' indicates an anagram.
'bent' becomes 'tails' (I can't explain this - if you can you should give a lot more credence to this answer).
'on' is an insertion indicator (as in clothing \'on\' a person).
'one' anagrammed gives 'oen'.
'oen' inserted inside 'tails' is 'TOENAILS'.
Can you help me to learn more?
(Other definitions for toenails that I've seen before include "Extremities" , "types of digital hardware" .)