Virtuoso Layout L: Show/remove hidden/old (metal) layers

Hi,

I have a design which I migrated from a 10 metal stack to a 8 metal stack.

It seems that the two "unsupported" metal stacks are still in the layout but I do not find any way to show and remove them. They are not listed as layers (because they do not exist in this PDK).

When I run DRC, I get the error of the unsupported metal layers. After clicking on the DRC error, the regions are highlighted where the metals are (and are supposed to be). But I find no way to mark and remove them.

Thanks!