Scrap iron finally extracted from odd hobnails (7)
I believe the answer is:
abolish
'scrap' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for abolish that I've seen before include "delete" , "Nullify" , "Put an end to (something)" , "ditch" , "Terminate" .)