Dust off the edges of its composition (5)
I believe the answer is:
motet
'composition' is the definition.
(I've seen this in another clue)
'dust off the edges of its' is the wordplay.
I cannot really see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
'of' could be 'o' and 'o' is found in the answer.
The remaining letters 'met' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for motet that I've seen before include "Something to sing" , "Musical composition" , "Short sacred choral work" , "Church choral composition" , "Anthem or church cantata" .)