Crossword Genius

Warm shoe currently black, covered in black powder (4-4)

Ross

I believe the answer is:

snow-boot

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'warm shoe' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.

'currently black covered in black powder' is the wordplay.
'currently' becomes 'now' (right now).
'black' becomes 'b' (abbreviation as in pencil classifications).
'covered in' is an insertion indicator.
'black powder' becomes 'soot' (I've seen this before).
'now'+'b'='nowb'
'nowb' inserted into 'soot' is 'SNOW-BOOT'.

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I've seen this clue in The Times.
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