The most common and most likely answer to this crossword clue is the 6 letter word BEAKER
I've seen this crossword clue in The Times
B
E
A
K
E
R
More clues leading to the result BEAKER
- Tradesman swallowing last of coffee in cup
- Drug-injecting worker in need of dough's a mug
- A barrel, say, runs out when filling beer container
- He makes dough defending European Cup
- Muppet mug
- Vessel less inviting when litre’s not provided
- One of three men in tub trapping behind in the vessel
- Cook putting last bit of cheese in container
- Hooter preceding the Queen’s Cup
- Lab equipment one dismantling right away
Buddy explains!

The straight part
We know that "mug" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case mug = beaker.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 BEAKER mean?
BEAKER noun- A flat-bottomed vessel, with a lip, used as a laboratory container.
- A drinking vessel without a handle, sometimes for the use of children.
- A mug.
- (Antarctica) A scientist.