Queen twice held as a rubber (6)
I believe the answer is:
eraser
'a rubber' is the definition.
(rubber can mean an eraser)
'queen twice held as' is the wordplay.
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'twice' shows that letters should be duplicated.
'held' is an insertion indicator.
'er' duplicated is 'erer'.
'erer' going around 'as' is 'ERASER'.
(Other definitions for eraser that I've seen before include "A student's rubber, or the one who uses it" , "Item used for rubbing out" , "A schoolboy's rubber" , "Rubber for removing marks" , "(Pencil, ink) rubber" .)