Nares troubled with her fire — what can get rid of nasty smell? (3,9)
I believe the answer is:
air freshener
'what can get rid of nasty smell?' is the definition.
(an air freshener removes bad smells)
'nares troubled with her fire' is the wordplay.
'troubled with' indicates anagramming the letters.
'her'+'fire'='herfire'
'nares' with its letters anagrammed with 'herfire' can make 'AIR-FRESHENER'.
(Other definitions for air freshener that I've seen before include "Disguiser of domestic smells" , "it clears a bad atmosphere" , "Room scent" , "Domestic scent" , "Scented spray" .)