Mistake remover (6)
I believe the answer is:
eraser
'mistake remover' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for eraser that I've seen before include "Rubbing-out device" , "Rubber, thing that wipes out" , "One who removed" , "Implement for rubbing out" , "device for deleting things" .)