wiping data off a hard drive

Hi everyone, I have a problem with a portable usb 2G micro hard drive.
I use(d) it a lot and now it has decided to stop working. Worst case
and most likely cause is that its a problem with the interface
electroncs rather than the physical disk. The problem for me is that
the store will happily give me a refund (they have confirmed the item
is defective) however they will need to send it back to the
manufactucturer so they can ascertain what is wrong. So, as there is
personnel data stored on the device (assuming there is nothing wrong
with the disk) I'm reluctant to just give it back. Initially their
customer service told me they'd test it first and if they couldn't fix
it they'd destroy it in my presence. So, does anyone know if it is
possible to wipe data from a disk without physically connecting to a
computer. Examples say a microwave, or strong magnets. I've heard all
the possibilities but literally with domestic appliances what actually
is possible?

Thanks if anyone cane come up with a solution for me and merry
christmas to everyone.

Tim