Do you wonder where .trashes folder and ._. trashes hidden folders on your USB came from? Actually this files are not harmful to your device, as this folders are automatically created whenever you use your USB flash drive in a computer running an Apple Mac operating system.
Why .Trashes Folder Appear on Your USB Drive
.Thrashes folder basically contains all the trash files executed on Mac OS where you used to connect your USB/Flash drive. You can delete this files anytime you can if you need extra space or if you are organizing your folders on flash drive.