Old streetcar filled evenly was not hot at all (5,4)

I believe the answer is:

extra mild

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'not hot at all' is the definition.
I don't know anything about this answer so I cannot judge whether this works.

'old streetcar filled evenly' is the wordplay.
'old' becomes 'ex' (prefix meaning former or onetime).
'streetcar' becomes 'tram' (synonyms).
'evenly' indicates alternate letters (the letters in even-numbered positions).
The alternate letters of 'filled' are 'ild'.
'ex'+'tram'+'ild'='EXTRA MILD'

'was' acts as a link.

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I've seen this clue in the Sydney Morning Herald.

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