How can I open or read /textClipping files from early- or pre-OS X systems

I have text clippings (.textClipping) from various previous Mac systems ranging through System 8 and all the various OS X versions.

On BigSur, these appear blank. On previous systems they also appeared blank, but (weirdly) I could still cut'n'paste the text, but not with BigSur.

I've tried:

1. a heavily-promoted site (loaded with annoying pop-ups) that promised to convert them online, but no result.
2. using DeRez in devTools (as another answer suggested) to no avail.

I do have older Macs with previous OS X versions, but I really need a way to extract the text from a modern Mac - there must be a load of people with the same issue!

Solution 1:

Text clippings are still a valid and supported format: I can create them and view them in MacOS Monterey.

Interestingly, if I change the file format to .txt or .rtf, they remain 'clippings' -- opening into a window in the Finder itself, rather than as document in TextEdit or other.

This window is copyable.

You can open the file in a text editor, like BBEdit, and may be able to glean the contents from the RTF and XML data inside.

But I suspect that your files may be corrupted in some way. It's possible that the early versions of these files were resource fork data, which has since been stripped from the file.

EDIT: I've performed a quick test: open Sheepshaver, the Classic Mac OS emulator, and create a text clipping in OS 9. Zip it (with DropStuff!), transfer to Monterey disk, unzip.
There is nothing there: the file is 0Kb.

It's likely that old textclippings are no longer supported. I would begin the process of converting all your clippings on your older Macs as soon as possible.