I still have a few floppy disks packed away at the loft, but I wonder if they still work the next time I turn on my BBC or Archimedes.

My collection of 5 1/4" floppies were mostly fine, after some thirty years. I think I had one or two (of very many) with read errors. 3.5" floppies though.. just about every "HD" (1.44MB) ones were a goner. The "DD" (720kB) fared much better.

The last time I checked, the only 5,25" floppies that still worked from that age were the ones in those Acornsoft covers.

I recently repaired an Apple II that were stored in a binder in an environment that wasn't climate controlled (for ~35 years). The 5.25" floppies had all developed a layer of stickiness, but all but one read fine once I cleaned up the drives.

I'd suggest grabbing a greaseweazle[0] ahead of that.

0. github.com/keirf/greaseweazle/