The most common and most likely answer to this crossword clue is the 5 letter word LATEX
I've seen this crossword clue in The Times
L
A
T
E
X
More clues leading to the result LATEX
- Tangerine's skin in sloppy plant secretion
- What might have exuded from trees in former times
- Careless carrying tea, spilling a milky fluid
- Extremely twee in soft rubber
- Team’s one short after dead rubber
- Source of rubber unknown no longer?
- Overdue kiss, it’s rubbery
- State supports the Parisian that’s in rubber
- Rubber solution from past times
- Paint at a time well after dark, ten
Buddy explains!

The straight part
We know that "milky fluid" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case milky fluid = latex.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 LATEX mean?
LATEX noun- A clear liquid believed to be a component of a humour or other bodily fluid (esp. plasma and lymph)
- The milky sap of several trees that coagulates on exposure to air; used to make rubber.
- An emulsion of rubber in water, used in adhesives and the like.
- Natural latex rubber, especially non-vulcanized rubber, such as is used in making latex gloves, latex condoms, and latex clothing.