[vcf-midatlantic] USB Floppies that are flexible? Cleaning a 3.5" drive?

[John Heritage]

Hey folks,  two asks -- I'm looking for advice:

Are there any USB or external floppy drive arrangements that are flexible
like internal floppy drives for allowing formatting and/or reading of
unusual sector sizes or formats?

Ex:  800KB Atari ST floppies and PC DOS disks formatted in unusual sizes

..

Second question is -what is the easiest way to clean the heads on a 3.5"
floppy?   If I have a bunch of 'suspect' floppies that I want to clean the
head between every disk it seems a little painful to disassemble the drive
enough to see the heads and clean.  Are there any alternatives?

(I'm used to 5.25" drives where there's often enough space in there to wipe
without disassembly).
Maybe there's a good (modern) source of 3.5" cleaning floppies?

(P.S.  I have a K6-3+ PC I can put a fresh OS on so I may be cleaning a
legacy 3.5" drive instead of a USB floppy).

Thanks!
John