Novello takes years finding key (5)
I believe the answer is:
ivory
'key' is the definition.
(I've seen this before)
'novello takes years' is the wordplay.
'novello' becomes 'ivor' (I've seen this in another clue).
'takes' means one lot of letters go next to another.
'years' becomes 'y' (abbreviation).
'ivor'+'y'='IVORY'
'finding' acts as a link.
(Other definitions for ivory that I've seen before include "Creamy white" , "Elephant tusk material" , "What may be carved" , "on either side of trunk" , "Cream" .)