I am working on an old drawing in V10 which has been copied over itself, i.e. on each layer there are 2 of each entity on top of each other. Is there a macro or some other way of deleting multiple lines. I have this as a ruby script in SketchUp.
You can use the HLR with the Save Image toggled on: make each layer Active Only and save the image to a layer file. Then load each layer file back into the layer that it came from.
This will work if they are straight lines -- arcs get chopped up into tiny bits, and text also gets messed up, so i'd recommend erasing these by Entity, one at a time.