Cleaning item badly rusted (6)
I believe the answer is:
duster
'cleaning item' is the definition.
'badly rusted' is the wordplay.
'badly' is an anagram indicator.
'rusted' with letters rearranged gives 'DUSTER'.
(Other definitions for duster that I've seen before include "Rusted (anag)" , "Cloth for cleaning chalk from blackboard" , "Soft cloth for cleaning surface" , "Cloth for removing surface powder" , "Polishing cloth" .)