Get away with small fine about adulterated food (3,3)

I believe the answer is:

sod off

'get away' is the definition.
(rude instruction to go away)

'small fine about adulterated food' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'fine' becomes 'f' (abbreviation in pencil classifications).
'about' indicates putting letters inside.
'adulterated' indicates anagramming the letters (adulterated can mean spoiled).
's'+'f'='sf'
'food' anagrammed gives 'odof'.
'sf' going around 'odof' is 'SOD OFF'.

'with' is the link.

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.