The most common and most likely answer to this crossword clue is the 9 letter word GELIGNITE
I've seen this crossword clue in The Guardian
G
E
L
I
G
N
I
T
E
More clues leading to the result GELIGNITE
- Explosive, say, hurled back coal
- One third of German coal is explosive
- Turn on light and get cracking with this?
- Surprised expression about renovated tiling ā factor in altering mine?
- Explosive switched for one type of coal
- Good and exceptionally gentle, I repeatedly can be explosive
- Banger turned on fire
- Iām surprised about tiling being shattered ā by this?
- Set light to powerful explosive
- Angel ignites concealed explosive
Buddy explains!

The straight part
We know that "get cracking with this" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case get cracking with this = gelignite.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GELIGNITE mean?
GELIGNITE noun- An explosive mixture of nitroglycerine and nitrate absorbed onto a base of wood pulp.