When you say the trash bin is empty, does that mean you have emptied the Trash directory which should be in your /home/username directory.
/home/username/.local/share/Trash. If you do this using a file manager, you will need to enable view hidden files as the '.local' directory is hidden. In the Trash directory, you will see two sub-directories named 'files' and 'info' and you can delete anything there. If you have already done this, I'm not sure what else you could do.