Jam quietly disposed of, or set aside? (7)
I believe the answer is:
reserve
'set aside?' is the definition.
('reserve' can be a synonym of 'set aside')
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for reserve that I've seen before include "left on the bench?" , "Book - substitute player" , "keep for oneself" , "cool" , "Hold back" .)