The most common and most likely answer to this crossword clue is the 6 letter word SPIRTS
S
P
I
R
T
S
Buddy explains!

The straight part
We know that "fine jets" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fine jets = spirts.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 SPIRTS mean?
SPIRTS verb- To cause to gush out suddenly or violently in a stream or jet.
- To rush from a confined place in a small stream or jet.
- To make a strong effort for a short period of time.