Here is a nifty trick for those who mainly use AutoCAD based products but have access to a Revit license. I often get files to start projects that have a gazillion frozen or off layers. When I want to delete all these layers, I would normally use the Layer Properties Manager to lock the visible layers and then make the not visible... well visible. The I could delete the originally not visible and unlock the rest with a purge to top it off.
I don't know if this is easier, but it's and option. Open Revit and select the Import\CAD Formats from the File menu. In the Import\Link dialog chose only to import the visible layers as indicated below.
Finish by exporting that view back to AutoCAD. You can also hand pick layers using the select option, but I find you might as well open the Layer Properties Manager at this point, because Revit takes just as long to show you all the layers as AutoCAD does.
Now get back to work, somebody out there is waiting on their red lines.