Grammar fix
polish off
finish all the food
eat or drink the whole of something, finishing it completely
phrasal verbB1common
Hear it in context
Notice where the phrase sounds natural.
He polished off the whole packet of biscuits in one sitting.
Go on, polish that off — I don't want it going to waste.
Fix the pattern
One small grammar move makes it sound right.
Confusing with 'polish' (to clean) — the phrasal verb is about finishing food.