After mix-up in pit man at last removed drums (7)
I believe the answer is:
timpani
'drums' is the definition.
(type of drums)
'after mix-up in pit man at last removed' is the wordplay.
'after' is a charade indicator (letters next to each other).
'mix up in' indicates anagramming the letters (I've seen 'mixed up in' mean this).
'at' says to put letters next to each other.
'last removed' becomes 'i' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'pit'+'man'='pitman'
'pitman' with letters rearranged gives 'timpan'.
'timpan'+'i' is 'TIMPANI'.
Can you help me to learn more?
(Other definitions for timpani that I've seen before include "Mini tap on a large drum" , "Set of kettledrums" , "Features of kitchen" , "Those beaten" , "Percussion instrument" .)