In husband’s absence, warm through and polish off (3,2)
I believe the answer is:
eat up
'polish off' is the definition.
(polish off can mean to eat)
I can't explain the rest of the clue.
(Other definitions for eat up that I've seen before include "Devour entirely" , "Empty plate" , "show good appetite" , "Finish one's food" , "43 [TUCK] in" .)