wipefs can remove signatures, labels, and RAID info from block devices. In some cases, gdisk will recommend using it.
By default, will show them:
/sbin/wipefs /dev/sdc
From a USB drive imaged with an Ubuntu .img file:
offset type
----------------------------------------------------------------
0x1fe dos [partition table]
0x8001 iso9660 [filesystem]
LABEL: Ubuntu-Server 16.04.2 LTS i386
UUID: 2017-02-15-20-43-45-00