Several times I have seen posts of people wanting to recover data from floppies. Since this is a difficult and sometimes complex issue – having lots of variables on data types, formats and maybe encryption – will try to create general guidelines or best practices to recover most data.
First of all we need to physically analyze the disk, look for creases, marks or plain dirt. Also look inside the sleeve, as the “padding” material could be dirty or moldy.
If there’s visible dirt, cleaning the media would help, but you need to be VERY CAREFUL. Try to use something that gently can move the disc like the drive does, and with cotton swabs or lens cleaning cloths you can softly clean them damped in 70% isopropyl.
After that, don’t forget to clean the heads before starting.It is recommended to use Floppy disk cleaning kits, that use a floppy with special disc made of non abrasive material that you damp with isopropyl alcohol.
Then read it with AppleSauce’s Fast Imager, do a “Retry Bad” if needed. If you start getting entire tracks of red, stop it and clean the drive head. Retry bad, retry bad, retry bad.
At this point most likely you have restored the data. If not, extreme measures may need to be taken. Consider that maybe the data may be unrecoverable, and proceed to cut open the disk sleeve and take out the disk itself. Use gloves to do this. You can try cleaning it GENTLY with soap and water, then dry it with as cloth or soft tissue. Remove GENTLY any dust from the surface, maybe with canned air.
After cleaning, consider putting it back into another sleeve if you can, in case the old sleeve is dirty inside.
Try Fast Imager again, hopefully data will be recovered, if fails, most likely is irrecoverable.
Applesauce device – https://applesaucefdc.com/
Disk cleaner – https://www.floppycleaner.co.uk/
Cleaning disks video – https://www.youtube.com/watch?v=d10rdDLEDfo&t=1s