Unimportant museum piece, wrought iron (5)
I believe the answer is:
minor
'unimportant' is the definition.
(I've seen this in another clue)
'museum piece wrought iron' is the wordplay.
'museum piece' becomes 'm' (I can't justify this - if you can you should give a lot more credence to this answer).
'wrought' indicates anagramming the letters (I've seen this in other clues).
'iron' with letters rearranged gives 'inor'.
'm'+'inor'='MINOR'
Can you help me to learn more?
(Other definitions for minor that I've seen before include "Adolescent" , "Little-known" , "Trivial" , "Less important" , "Of little significance" .)