Grime or dust (4)
I believe the answer is:
dirt
I believe this clue is a double definition.
'grime' is the first definition.
(synonyms)
'dust' is the second definition.
(thesaurus)
(Other definitions for dirt that I've seen before include "Scandalous information" , "Loose soil; filth" , "scandalous gossip" , "Scandalous info; earth" , "Grime, filth" .)