Coaches may turn to rust (6)
I believe the answer is:
tutors
'coaches' is the definition.
(I know this)
'turn to rust' is the wordplay.
'turn' indicates anagramming the letters.
'to'+'rust'='torust'
'torust' anagrammed gives 'TUTORS'.
'may' acts as a link.
(Other definitions for tutors that I've seen before include "Private instructors" , "Teachers of individuals or small groups" , "Coaches" , "Private teachers for students" , "Mentors" .)