Wow! What a great discovery.
There are probably lots of such frags repurposed as mummy wrappings. Given the advancements in non-invasive methods of coaxing out texts (like the Villa of the Papyri scrolls) CAT scans and whatnot of the mummies might prove quite fruitful, particularly in the so-called Valley of the Golden Mummies, where the Roman-era hoi polloi got the old school treatment but probably on the cheap.
The first Mummy’s Day card?