Ask to remove top? Go ahead! (4)
I believe the answer is:
lead
'go ahead' is the definition.
(I've seen this in another clue)
'ask to remove top?' is the wordplay.
'ask' becomes 'plead'.
'to remove top?' means to remove the first letter (I've seen 'removes top' mean this).
'plead' with its initial letter removed is 'LEAD'.
(Other definitions for lead that I've seen before include "Short wire used as jumper - Pb" , "conductor of electricity" , "First put down spade, say" , "One with starring role" , "Metal -- Pb" .)