Burn printed music mostly used by church (6)
I believe the answer is:
scorch
'burn' is the definition.
(scorch is a kind of burn)
'music mostly used by church' is the wordplay.
'music' becomes 'score' (score is a kind of music).
'mostly' means to remove the last letter.
'used by church' becomes 'ch' (I can't explain this - if you can you should believe this answer much more).
'score' with its last letter taken away is 'scor'.
'scor'+'ch'='SCORCH'
'printed' acts as a link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for scorch that I've seen before include "Burn on the surfaces" , "Burn until black" , "Burn lightly" , "Mark by overheating" , "Wither from exposure to heat" .)