How to Empty Trash of root user in Ubuntu


Install nautilus-gksu
About Nautilus-gksu

Privilege granting extension for nautilus using gksu
The gksu extension for nautilus allows you to open files with administration privileges using the context menu when browsing your files with nautilus.

Reboot computer after installing nautilus-gksu 
Open your home folder.
Right click on any folder and click Open as administrator.
You will enter root user.
On the left pane you will see root home.

Go to /root/.local/share/Trash/files
Delete the files you don’t want.
All Done !!
Close the window and your root trash is emptied.