If this is some USB drive that belongs to you and you know it hasn't been tampered with, you can assume it will be safe after you rebuild the partition table and overwrite it with zeros.
If it doesn't belong to you or you suspect that it might have been tampered with, but you are still sure it is a legit USB device and won't just fry your motherboard with a capacitor discharge the moment you plug it, you should still consider the possibility that it might be not what it looks like.
It is possible for an adversary to implant a USB hub, a storage drive and a malicious hardware in the same package (and it was done before), making it into a hardware trojan.
Imagine this: a user plugs in what he thinks is a USB drive, while on the background a malicious device that uses the same hub stealthily installs it's payload through a malicious driver or a keyboard emulator.
If it is some device that you found on the street: JUST DON'T. You can never be sure that it is not something like a USB killer that will fry your 100$ motherboard or 1000$ laptop: