re-use old live USB for new LL iso?

[Moltke]

Thanks to all for the replies.

I did try gparted on a few USBs and an SD, but none appeared in the list.

I tried TMG's method and that did see the usb and SD which I tried. I got as far as "type 1 to select....." but the response was "could not delete partition". 
I'm not sure if what I tried previously using some utility or other on Windows hasn't scrambled things a bit.

KPanic - what does the command 'sudo cat imagefile > /dev/sdc' do?

Did/do you use this USB stick in Windows too? I mean, have you recently plugged it in into a Windows pc? It might be infected with some virus. A friend of mine recently asked me to see if I could fix her USB flash drive cause she couldn't access it, she uses windows and she told me it is infected and by extension the flash drive, so I took the drive home and tried to format it using different methods; gparted, dd, shred, testdisk and a few others I can't remember now, none of them worked; the drived ejected itself every time. After a week trying to fix it I gave her back and told her that I was unable to do it, I did rescue the data but the drive was unusable itself. I don't know if this is your case but it might be a good idea to confirm whether it is the case or not.

Hope this helps!