In Ubuntu, each drive has a hidden trash bin, just like in Windows. But in Ubt, "undelete" is integrated. This works for native Linux file system formats ext?, and old Windows FAT32, but somehow don't work for new Windows NTFS with multiple partitions.
Users see a single trash bin accessible via the status bar. When a drive is mounted, it's trash appears in the central trash bin. A flash drive is automatically mounted when it's inserted.
In the desktop GUI, Gnome, you cannot delete a file, but only move it to the trash. So you don't recover disk space when you remove files on the flash file. You have to empty the trash.
For some reasons, probably pulling out the flash drive without unmounting it first, and didn't empty the trash first, the trash can information got corrupted. Say the trash can cannot be emptied.
First, you have to become superuser to force delete files in trash can. You need to bring up the file explorer or file browser in Linux:
From there you browse the the flash drive, show hidden files via options. Then you have sufficient privilege to delete files in the Trash can.