People believe in deleting files from pen drives or hard disks, but it does not mean that data is permanently gone. The data can be recovered using simple software program by professionals. Dropping them at e-waste plants also carries a potential risk of elements trying to recover data.
The old floppy drives, do not take up much space, you can store it in one corner. People have used these innovatively as small table mats for cups and office small decorative plants etc.
If you remember the old floppy disks they are similar to a cassette player or a VCR tape. It has a thin disc that is coated with a ferromagnetic material which is in turn enclose in a plastic casing. It is easy to pry open this floppy with a sturdy sharp knife tip (caution while using sharps). Once we do this, the outer plastic and the non-vital metal parts can be disposed easily. The inner disc ( very small in volume/weight) can be shredded with a good scissors and then disposed either by burning/ soaking in acid with care.
The same can be followed with the modern pen drives by taking put the memory board from the case and the USB connector end.
The best ways to prevent data from being recovered or stolen is to physically destroy the inner mother board of a pen drive or a hard disk. Professional companies handling sensitive data use methods like breaking down the memory board and burning it or soaking it in acid solution. Both need to be done carefully so that we are not exposed to noxious fumes or risk acid burns.