The most common and most likely answer to this crossword clue is the 6 letter word WASHER
I've seen this crossword clue in The Times
W
A
S
H
E
R
More clues leading to the result WASHER
Buddy explains!

The straight part
We know that "Ring/cleaner" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ring/cleaner = washer.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 WASHER mean?
WASHER noun- Something that washes; especially an appliance such as a washing machine or dishwasher.
- A person who washes (especially clothes) for a living; a washerman or washerwoman.
- A flat disk, placed beneath a nut or at some joint, to distribute pressure, alleviate friction or prevent leakage.
- A face cloth.
- To fit (a mechanical device) with a washer.