Can't delete file from trash as root
I'm using Ubuntu 16.04 and deleted a file as root to trash. Then I couldn't delete it because root nautilus won't view trash, and I installed bleachbit and used it as root but it won't clean it either.
To delete a file as root you need to open nautilus as root by typing in terminal
sudo -H nautilus
Then inside nautilus use the shortcut CtrlH to show the hidden files. After that navigate to /home/username/.local/share/Trash/files.
And delete the files easily.