Some deliver a sermon in rubber! (6)
I believe the answer is:
eraser
'rubber' is the definition.
(rubber can mean an eraser)
'some deliver a sermon' is the wordplay.
'some' says the answer is hidden in the clue (some parts of the word are used).
'ERASER' is hidden in the letters of 'deliver a sermon'.
'in' acts as a link.
(Other definitions for eraser that I've seen before include "Rubber, thing that wipes out" , "(Pencil, ink) rubber" , "Obliterator" , "What a poor artist needs" , "device for deleting things" .)