Milkman picks them up to spite me, somehow (7)
I believe the answer is:
empties
'milkman picks them up' is the definition.
I can't judge whether this defines the answer.
'spite me somehow' is the wordplay.
'somehow' indicates anagramming the letters.
'spite'+'me'='spiteme'
'spiteme' with letters rearranged gives 'EMPTIES'.
'to' is the link.
Can you help me to learn more?
(Other definitions for empties that I've seen before include "Vacates" , "drains" , "Bottles after the contents have been poured out" , "Returned bottles" , "they've nothing to offer" .)