Chests of heavy smokers by the sound of it (7)
I believe the answer is:
coffers
'chests' is the definition.
(I know this)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for coffers that I've seen before include "Money-chests" , "Treasury boxes" , "Financial resources or money boxes" , "Funds, financial resources" , "Treasury funds" .)