Bird goes round picking up drugs and used rubber (7)
I believe the answer is:
retread
'bird' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for retread that I've seen before include "modified tyre" , "what may be spare" , "film much the same as the one before" , "Second-hand tyre" , "One much improved in rubber" .)