Cast-off worker sad to receive note (4,2,4)
I believe the answer is:
hand-me-down
'cast-off' is the definition.
'worker sad to receive note' is the wordplay.
'worker' becomes 'hand' (hand is a kind of worker).
'sad' becomes 'down' (I've seen this before).
'to' is a charade indicator (letters next to each other) (I've seen this in other clues).
'receive note' becomes 'me' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'down' put after 'me' is 'medown'.
'hand'+'medown'='HAND-ME-DOWN'
Can you help me to learn more?
(Other definitions for hand-me-down that I've seen before include "Passed-on clothing" , "Second-hand garment" , "Item passed on" , "Garment passed on to another" .)