The most common and most likely answer to this crossword clue is the 3 plus 3 letter word TIN CAN
I've seen this crossword clue in Financial Times
T
I
N
C
A
N
More clues leading to the result TIN CAN
- What preserves time of ancient civilisation
- Temperature of old Peruvian container
- Cat prancing round popular end of town – full of beans maybe?
- Metal container, earliest in trove, related to an ancient culture
- I can’t recycle new container
- Sealed container of ancient civilisation found after short time
- Container that’s brown put outside home, third for recycling
- One may be full of beans, after short time behind bars
- Container, container, container
- Front of that old Peruvian container
Buddy explains!

The straight part
We know that "Metal container" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case metal container = tin can.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.