Danny, The problem with layerfilters arises because when you copyclip anything (be it a line, block, or half the dwg) from one dwg to another it copies all the layerfilters and layerstates. It is not too bad with layerstates as most people don't use them that much, it is a different story with layerfilters. We were routinely having dwgs with 20,000 to 30,000 layerfilters. Well I loaded that piece of code into our office mnl file to run at dwg startup, and server storage usage went from 36GB to 25GB over about 30 projects. WOW!
I'm only on A2K, but I think this is correct so others correct me if I'm wrong, isn't the problem resolved in 2004-5?