The most common and most likely answer to this crossword clue is the 6 letter word STEROL
I've seen this crossword clue in The Daily Telegraph
S
T
E
R
O
L
More clues leading to the result STEROL
- Chemical left at the bottom of store exploding
- Way traditions upset compound
- Many standing up to drink monarch's alcohol
- Solid alcohol that gets ostler reeling
- Good person learning about alcohol
- Pious person learning about alcohol
- Saint learning about alcohol
- Pulling up unopened broccoli heads, say, yields waxy stuff
- Chemical store exploding — hell ultimately
- Waxy stuff coming from master, old
Buddy explains!

The straight part
We know that "Waxy stuff c" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case waxy stuff c = sterol.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 STEROL mean?
STEROL noun- Any steroid that contains a hydroxyl group in the 3-position of the A-ring.