The most common and most likely answer to this crossword clue is the 5 letter word BESOM
I've seen this crossword clue in The Daily Telegraph
B
E
S
O
M
Buddy explains!
The straight part
We know that "cleaner" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cleaner = besom.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 BESOM mean?
BESOM noun- A broom made from a bundle of twigs tied onto a shaft.
- A troublesome woman.
- Any cleansing or purifying agent.
- To sweep.