Desk item (6)
I believe the answer is:
eraser
'desk item' 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" , "correction device" , "One removes writing" , "A student's rubber, or the one who uses it" , "Required, should you make a mistake" .)