LiveInTheWorld(AndStillBeHappy), se você lê e entende inglês, veja abaixo os sentidos de "dust (it) off":
1 to get something ready to use that you have not used for a long time
I’m dusting off my old skills and returning to work.
Synonyms and related words
To use something, or to be used:repurpose, upcycle, go towards...
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2 to wipe dust or dirt off the surface of something
Would you dust off the shelves?
Synonyms and related words
To make things cleaner or tidier:clean up, clear out, clean...
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3dust yourself off to wipe dust or dirt off your clothes
Synonyms and related words
To make things cleaner or tidier:clean up, clear out, clean...
Fonte:
http://www.macmillandictionary.com/dict ... h/dust-off