Use obtar -Xunlabel to unlabel volumes. Unlabeling a volume causes all information stored on it to be effectively erased, including any existing volume label information.
obtar -Xunlabel [ -f device ] [ -Xow ]
You can specify a number of options with obtar -Xunlabel; this section describes those options that you are most likely to use. Refer to "obtar Options" to learn about additional obtar -Xunlabel options.
Specifies the name of the device in which the volume is loaded. The device argument to -f is the name that you have assigned to a tape drive in an administrative domain.
Directs obtar to disregard any expiration date in the volume label. If you try to overwrite a volume that has not yet expired, then the operation fails unless you specify -Xow.