There are 3 articles in Amiga Future magazine in issues 87 to 89, that explain how to literally clean your floppy disks with 'ECover' multi-surface surfactant - it's a process that you have to be careful not to get the fluid on the adhesive pad between the magnetic media and the metal centre shim/hub that attaches the magnetic media to the hub.
This method is very successful at cleaning a floppy disk, and either recovering data that appears initially to be lost or damaged, but once cleaned the disk reads as it was when it was virtually new.
At least that's what I've found.
The magazines on Amiga Future are free to read up to issue 85, so if you wait a few months I'm sure you'll be able to read those articles for free, or of course you could possibly get a back-issue from Amiga Future, if they've not all sold out.
