How to refresh a Mesh Brep?

I have a filter = Stream Filter with two inputs:

0) = Many Spheres

1)  = Many Boxex

I want to mesh either one, but after I do this, both of them stay in memory of the Mesh Brep... and I apply color to the new Mesh, but Both of them stay in Memory! 

I want, only one to pass the filter and go to the mesh and then, the mesh to reprsent only one!

Thanks!