The most common and most likely answer to this crossword clue is the 5 letter word LOOFA
I've seen this crossword clue in The Guardian
L
O
O
F
A
More clues leading to the result LOOFA
- John with odd bits of foam sponge
- Creamy mixture tipped on a sponge
- A dessert served up: Uncle Sam’s sponge
- Start off haughty meeting a cleaner
- What’s found in bathroom of India, ultimately?
- Bring up a kid to sponge
- Somewhere to go with Fanny Adams for rubber?
- Back scrubber turning a trick
- A dessert turned into sponge
- Scrubber taking a plonker from behind
Buddy explains!

The straight part
We know that "Back scrubber" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case back scrubber = loofa.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 LOOFA mean?
LOOFA noun- A tropical vine, of the genus Luffa, having almost cylindrical fruit with a spongy, fibrous interior; the dishcloth gourd
- The dried fibrous interior used as a sponge for bathing
- Any bathing sponge