Stoking boiler for Rocket? (8)
I believe the answer is:
firework
This clue is a double definition.
'stoking boiler' is the first definition.
(stoking a boiler is working with fire)
'rocket?' is the second definition.
(rocket is a kind of firework)
'for' is the link.
(Other definitions for firework that I've seen before include "fountain, say" , "Pyrotechnic device" , "Colourful incendiary device used for entertainment" , "Banger, for example" , "rocket" .)