Drudge changing bather's towel (6-6)
I believe the answer is:
bottle-washer
'drudge' is the definition.
(I know that bottle washer is a type of drudge)
'changing bather's towel' is the wordplay.
'changing' is an anagram indicator.
'bathers'+'towel'='batherstowel'
'batherstowel' anagrammed gives 'BOTTLE-WASHER'.
(Other definitions for bottle-washer that I've seen before include "Menial - factotum" , "Kitchen assistant" , "See 6" .)