First of all, there are plenty of tutorials on how to factory reset any massive storage device. For example, you can delete all it’s partitions and start a new full NTFS drive; it should be enough.
The danger is that you can’t reset the USB before it infects the computer where you mounted the drive, right? So we would need something like a sandbox or a discardable place to clean the USB.
Running the USB in a coffee shop where you can pay for some minutes of computer usage. If something happens there, you shouldn’t worry.
Mounting the drive on a discardable operative system. Whatever happens to the OS (I would suggest a Linux because it is easy to install and discard), you later delete it.
COMMENT: I’m not taking into account those tryhard USB devices which contain viruses by default or shall affect your BIOS or anything weird. Just a regular USB stick to which a virus has been set into the default storage.
Hope it helps!