The most common and most likely answer to this crossword clue is the 4 letter word RASP
I've seen this crossword clue in The Daily Telegraph
R
A
S
P
More clues leading to the result RASP
- Runs when piano produces rough sound
- Artist's first in personnel file
- Head of government failing to understand file
- Catch on topless grate
- It is used to grate fruit
- Because, in a manner of speaking, it sounds harsh
- File snake under heading for reptiles
- File useless in the end, hammer nails
- Jar for this berry?
- Runs when piano gives rough sound
Buddy explains!

The straight part
We know that "scratch" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case scratch = rasp.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 RASP mean?
RASP noun- A coarse file, on which the cutting prominences are distinct points raised by the oblique stroke of a sharp punch, instead of lines raised by a chisel, as on the true file.
- The sound made by this tool when used, or any similar sound.
- To use a rasp.
- To make a noise similar to the one a rasp makes in use; to utter rasps.
- To work something with a rasp.
- To grate harshly upon; to offend by coarse or rough treatment or language.
- The raspberry.