Sell spare part for piano, as one might say? (6)
I believe the answer is:
peddle
'sell' is the definition.
(peddling is a kind of selling)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for peddle that I've seen before include "Tout" , "Promote (an idea) widely or persistently" , "Sell from place to place" , "Sell from door to door" , "Travel around selling small items" .)