modern removable media drives

Two categories come to mind: 1. Something that physically or chemically removes or obscures the magnetic media. Gouging or scraping off the oxide coating qualifies, as does a chemical strong enough that it will dissolve the binder holding the oxide to the disk. Dust, hair, pepsi, and organge juice are generally too weak to do the damage necessary to prevent using the floppy (after cleaning, of course!). Aluminum oxide will do it :-). 2. Magnetic fields that are strong enough to overcome the coercivity of the media. I find that refrigerator magnets, in direct contact with low-density media (i.e. 5.25" 360Kbyte disks) will usually result in some bad sectors. With higher-density media, which has a higher coercivity, refrigerator magnets aren't strong enough in my experience. And unless you put the floppy in direct physical contact with the magnets in a PM motor or speaker, you aren't going to cause any damage. (I've worked with floppies and hard drives in close proximity to multi-Tesla cryogenic superconducting magnets without any problems, so speakers and motors don't scare me!) Tim.