So a cloth can be used as a source of heat (3,5)

I believe the answer is:

hot coals

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'as a source of heat' is the definition.
I don't know anything about this answer so I can't judge whether this works.

'so a cloth can be' is the wordplay.
'can be' indicates an anagram.
'so'+'a'+'cloth'='soacloth'
'soacloth' anagrammed gives 'HOT COALS'.

'used' is the link.

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