I used to have a .lsp file that would scan a drawing and select all the duplicate objects and allow them to be erased. AutoCad R14
 
I need a new .lsp file that is compatible with AutoCad 2000.
 
I have huge drawings that have been maintained since 1990 and throught the years have, for various reasons, acquired numerous duplicate objects.

Try the OVERKILL Express Tool (Bonus Tool).