Cleanup unwanted Projects from Unity Developer

I am very new to Unity, In my first steps of learning I have created several small projects.
I want to delete some of them, I have deleted them from my machine but the still show up under Projects in the Unity Developer page, there it is it possible to archive them, but I don,t want to waste space anywhere.
Please give me a hint.

in your project, choose settings and, at the bottom of the page, archive project.