Daredevil son to clean fastener with tip of rag (12)
I believe the answer is:
swashbuckler
'daredevil' is the definition.
(I know that daredevil can be written as swashbuckler)
'son to clean fastener with tip of rag' is the wordplay.
I cannot quite see how this works, but
'son' could be 's' (genealogical abbreviation for son) and 's' is found in the answer.
'clean' could be 'wash' (washing is a kind of cleaning) and 'wash' is located in the answer.
'fastener' could be 'buckle' (buckle is a kind of fastener) and 'buckle' is found in the answer.
A single letter 'r' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for swashbuckler that I've seen before include "Gascon" , "Errol Flynn on film, for instance" , "To prepare explorer" , "One given to derring-do" , "Daredevil" .)