You can just re-format them to ext. :) Any defrag tools there are ( and
there are only a few) are hard to use for newbies. They are commandline
tools that require a knowledge of device names and switches. Why put
yourself through the headache when you can avoid it? We use Linux for a
reason, so take advantage of its strengths. Besides, nothing stays long
enough on my FAT32 usb sticks to become fragmented and anything that is for
archival purposes are on a faster and more durable file system such as ext3
or 4.