Can't delete or modify elements

I am in Sketchup (latest version 2023) and even though I eliminated the host, the trees still persist in showing up in Vray. How do I get rid of them so I can start over? When I choose a host that Scatter says has NO trees, they still show up in Vray.

The host just lets Skatter know where to put the trees when you create the composition. The composition itself is not directly bound to the host.
You need to delete the composition in the Compositions Manager.