How to delete a collaborative space that is already empty?

Hello everyone

It's Carlos Vila from Polytechnic University of Valencia. I am applying Project Based Learning in our lectures for many years.

The problem I am facing is that after several academic course I am reorganizing and deleting several collaborative workspaces.

I do not why I have some of them totally empty but I cannot delete them.

Does anybody have an idea or suggestion?

Thanks in advance,

Carlos Vila 

Edu ​​​​​​​3DEXPERIENCE ​​​​​​​3DSpace ​​​​​​​