The most common and most likely answer to this crossword clue is the 6 letter word PAPYRI
I've seen this crossword clue in The Guardian
P
A
P
Y
R
I
More clues leading to the result PAPYRI
- Old manuscripts deliver cut below penny in wages
- Greek character collects a heap for burning, mostly old documents
- Old papers are of benefit with school subject, including piano
- Capital briefly storing pretty vacant old documents
- Secretary and detective conceal your Egyptian manuscripts
- Annual fire, with one replacing backmost ancient manuscripts
- Pray animatedly in Portuguese igreja initially and get ancient scrolls
- Pay Rip erroneously for writing materials
- Unprincipled snapper on the case of your independent manuscripts
Buddy explains!

The straight part
We know that "old documents" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old documents = papyri.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 PAPYRI mean?
PAPYRI noun- (usually uncountable) A plant (Cyperus papyrus) in the sedge family, native to the Nile river valley.
- (usually uncountable) A material similar to paper made from the papyrus plant.
- A scroll or document written on papyrus.