Waste chief sales device (4,6)
I believe the answer is:
loss leader
'sales device' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
'waste chief' is the wordplay.
'waste' becomes 'loss' (I am not sure about this - if you are sure you should believe this answer much more).
'chief' becomes 'leader' (I've seen this in another clue).
'loss'+'leader'='LOSS-LEADER'
Can you help me to learn more?
(Other definitions for loss leader that I've seen before include "Sees dollar (anag.)" , "Cheap attraction" , "Article sold at no profit in order to draw customers" , "bait for shoppers" , "Product sold cheaply to attract buyers" .)