Take away a part of French ventilation pipe (6)
I believe the answer is:
deduct
'take away' is the definition.
(I know that take away can be written as deduct)
'a part of french ventilation pipe' is the wordplay.
I cannot really understand how this works, but
'part' could be 'duct' (duct is a kind of part) and 'duct' is located in the answer.
'of french' could be 'de' ('of' in French) and 'de' is found within the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for deduct that I've seen before include "Subtract, take away" , "Knock off" , "Withhold" , "Remove" , "Make a subtraction" .)