Wear down some superhero demands (5)
I believe the answer is:
erode
'wear down' is the definition.
(to erode is to wear down or decay)
'some superhero demands' is the wordplay.
'some' says the answer is hidden in the clue (some parts of the word are used).
'ERODE' is hidden in the letters of 'superhero demands'.
(Other definitions for erode that I've seen before include "Wear away with weather" , "Grind down" , "Corrode" , "Eat away" , "'Deteriorate, wear away (5)'" .)