Use polymer endlessly for remoulding (6)
I believe the answer is:
employ
'use' is the definition.
('employ' can be a synonym of 'use')
'polymer endlessly for remoulding' is the wordplay.
'endlessly' means to remove the last letter.
'for remoulding' is an anagram indicator.
'polymer' with its final letter taken away is 'polyme'.
'polyme' with letters rearranged gives 'EMPLOY'.
(Other definitions for employ that I've seen before include "Hire; use" , "Engage or hire for work" , "Draw on" , "Take on (staff)" , "Give job to (someone)" .)