
Gnome Disk Utility can access it too while not mounted and you may try delete or format the partition, but that may just get an error: When the USB stick cannot be mounted by the system, Gparted would still access it, delete and create partitions. In this case, delete the partition in Gparted and create a new one.

It is made for writing images to USB sticks but it has an erase option.
Usb creator gtk for mac install#
Startup Disk Creator sudo apt-get install usb-creator-gtk

Sometimes, when even Gparted was unable to fix, re-create partition tables and format (see last part of this answer), this little tool was able to format it. When you have a live Linux system on an USB key it may be difficult to simply erase that drive. sudo add-apt-repository ppa:tsvetko.tsvetkov/trusty-backports It's Mint's alternative to Ubuntu Unity default Startup Disk Creator (see below) - only that the formatting tool is run as a separate GUI. My favorite is the USB Stick Formatter and the Image Writer from Linux Mint.

Therefore, the following should be seen as a complement to the other answer(s). Because sometimes erasing a drive can be tricky (see the cases mentioned below) I would recommend having different tools at hand for that purpose.
