I'm working on a drawing where all items are on layers set to colour 8. However the majority have had the colours changed in the object colour dropdown box. I have exactly 23676 items to now change back to bylayer so that all colours show as colour 8. The problem I have is when I 'select all' the object colour dropdown shows they are all by layer and therefore wont let me change them all at once. I have even tried changing them to red, yellow etc just to see if they change but they dont. I can however select a small group and then it will let me change these all together.
Is there any solution to changing all these at once because going through the drawing highlighting small areas and changing them is going to take me an eternity and I have four drawings the same.
 
Thanks

Try using the command "change" or "chprop" on the command line.