Right click on a group of render nodes, click Modify Pool...
Multiselect the pools you want to remove the machine from and hit Delete.
I get the idea that I should drag them out, but logic would also apply that hitting delete would just remove the machine from the pools, so when I accidentally hit delete and it just locks up monitor completely, well, that is just bad no matter which way it goes really...
Ideally it would remove them from the pools but hopefully it can just be at least patched so it doesn't kill Monitor.
Joe