The most common and most likely answer to this crossword clue is the 5 letter word PAILS
I've seen this crossword clue in Financial Times
P
A
I
L
S
Buddy explains!

The straight part
We know that "buckets" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case buckets = pails.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 PAILS mean?
PAILS noun- A vessel of wood, tin, plastic, etc., usually cylindrical and having a handle -- used especially for carrying liquids, for example water or milk; a bucket (sometimes with a cover).
- (In technical use) A closed (covered) cylindrical shipping container.