Unnecessary to remove last pins (7)
I believe the answer is:
needles
'last pins' is the definition.
The definition and answer can be both man-made objects as well as being plural nouns.
Perhaps you can see a link between them that I can't see?
'unnecessary to remove' is the wordplay.
'unnecessary' becomes 'needle' (I've seen this before).
'to' says to put letters next to each other.
'remove' becomes 's' (I can't explain this - if you can you should give a lot more credence to this answer).
'needle'+'s'='NEEDLES'
Can you help me to learn more?
(Other definitions for needles that I've seen before include "Pointers - goads" , "Rocks off Isle of Wight" , "Pins and - -" , "required by dressmakers?" , "nettles" .)