Back up any files you want to keep
Insert the USB drive into your computer
Open File Explorer on Windows or Finder on Mac
Select the USB drive
Delete all files and folders on the drive
Empty the Recycle Bin or Trash if needed
To erase everything completely, format the USB drive
On Windows, right-click the USB drive and choose Format
On Mac, open Disk Utility, select the USB drive, and choose Erase
Confirm the action and wait for it to finish
Safely eject the USB drive when done