Ketchup ruined coat, to amuse (6,5)

I believe the answer is:

tomato sauce

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'ketchup' is the definition.
The definition and answer can be both things that one consumes for nourishment as well as being singular nouns.
Perhaps they are linked in a way I don't understand?

'ruined coat to amuse' is the wordplay.
'ruined' indicates an anagram.
'coat'+'to'+'amuse'='coattoamuse'
'coattoamuse' is an anagram of 'TOMATO SAUCE'.

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I've seen this clue in The Mirror.

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