Cleans different pews one sits in (5)
I believe the answer is:
wipes
'cleans' is the definition.
'different pews one sits in' is the wordplay.
'different' indicates anagramming the letters.
'one' becomes 'i' (Roman numeral).
'sits in' means one lot of letters goes inside another.
'pews' anagrammed gives 'wpes'.
'wpes' enclosing 'i' is 'WIPES'.
(Other definitions for wipes that I've seen before include "Erases" , "Rubs clean" , "Forgets" , "Passes over with a cloth" , "Cleans with cloth" .)