Systems Manager David Shultz shows us how to merge layers in AutoCAD.
"The LayMrg command gives you the ability to merge two or more layers together so that the objects end up on the final target layer that you choose. The old layers that now contain no objects are removed, effectively merging the layers. It's precisely what you'd expect from a command named LayMrg.
"While this feature is very useful, the command can also be really helpful for getting rid of unwanted layers in your drawing. This has happened to all of us: You're working away and there's a layer in the drawing that refuses to be deleted! It is probably due to its use within a block, or perhaps a block within a block, and it can be a real nightmare trying to identify where the offending object is that is using it. A workaround to the problem is to just merge it with, say, layer 0, so that you get rid of the offending layer, and whatever was using it is now on Layer 0."
Notes from Cadalyst Tip Patrol: Managing a file's layers can be a daunting task, especially when you are working with data from other people. You don't know what's happened to the file while it was under the care of other individuals. If you use files from clients, vendors, or others outside your office, then there is no telling what you will get.
Getting the objects into specific layers will help you in so many ways. Using LayMrg is simple enough: Start the command, select an object on the layer you want to get rid of, and select more if you like. When your selection is complete, press Enter. Select an object on the target layer. All objects on the selected layers will be moved to the target layer. If you can't find any objects on the specific layer, type the letter N and press Enter to access the name feature. A list of the available layers in the file will be displayed and you can choose from that list. Once finished, the selected layers are deleted from the file.