Incendiary bomb material (6)
I believe the answer is:
napalm
'incendiary bomb material' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for napalm that I've seen before include "Petrol jelly used in flame-throwers" , "Flame-thrower jelly" , "attack with bombs" , "Incendiary substance" , "destroy by fire" .)