Rubbish, waste (5)
I believe the answer is:
dross
This clue is a double definition.
'rubbish' is the first definition.
(I've seen this before)
'waste' is the second definition.
(dross is a kind of waste)
(Other definitions for dross that I've seen before include "Lees" , "Impurity" , "Waste coal - rubbish" , "Refuse - dregs" , "Something of inferior quality" .)