Tim, you may find the easiest way to purge is to select all, copy and paste into new drawing, but save your original drawing as a different filename just in case you need to go back to it.
The, the note below is not a direct reply to your question, but rather toward an illustration as to some of the complexity which it is useful to know about when selecting a layer/block system. Here is a note I made for myself, applicable at least for Version 11.1 pro:
Note about layer property retention: In a copy and paste example, although all layers themselves copied over into the new drawing, only one of the blocks retained [door] layer properties in its content, the other block dropped the [carcass] layer properties onto layer 0. There is no explanation as to which was retained, the examples were very simple indeed The difference was that the retained objects were originally produced from extruded rectangles and the non-retained was created from a cube, shelled and boolean sliced, so maybe the boolean operations sever the layer information for copy and paste where layers are not pre-prepared, perhaps it's just that the information exceeds the space allocated. When layers were ready and waiting in the new drawing before the copy and paste, the layer properties within the blocks was retained.
There are many issues to consider regarding layer and block systems, and varying uses. I am sure a short book could be written on the subject.
Upon revisiting this post almost a year later, I can only confirm that layer transfer between drawings where blocks are involved is very inconsistent, with some layers even changing to different layers, especially if some layers were already present in the second drawing. Very frustrating and time wasting. V11pro. [Perhaps V17 is better but that lacks save as v10.5 which is my lifeline to VBA scripts.]
« Last Edit: April 25, 2010, 12:22:17 PM by Alan C »
Platinum 21. & Deluxe 21.
TC user since 1995. (version 3)