Cleaning item (8,3)
'cleaning item' is the definition.
This is all the clue.
(Other definitions for duster that I've seen before include "Cloth for removing surface powder" , "Rusted (anag)" , "yellow cloth" , "Polishing cloth" , "cleaner" .)
(Other definitions for mop that I've seen before include "Swab" , "Floor cleaner" , "Hair, unkempt" , "Bundle of soft material at end of stick for cleaning" , "Implement for washing floor" .)