How to make a floppy drive head cleaner
The read/write heads on a floppy drive collect dirt and metal oxide particles. This will eventually stop them reading reliably. Commercial cleaners are expensive now, due to little demand, but you can make a single-use stand-in.
Crack open a 3.5-inch diskette from the end furthest from its shutter. Slide out the flexible disk and pop out and keep the metal hub the drive uses to spin it. Trace the disk’s inner and outer edges on some thin card and cut it out.
Glue felt or cotton to one side of the card and glue the metal hub in place. Lightly wet the disc’s cloth face with isopropyl alcohol; otherwise, vodka will do, or even gin – you want a good solvent that won’t leave sticky residue.
While it’s wet, put your cleaning disk back in its case. Insert into the drive. Mac OS will complain it isn’t readable, but the heads still rub against the cleaning pad while it looks for a valid disk. Try formatting 10 times or so for best results.