We recieved some files from an architect and they contained a bunch of stuff that has been since embeded into our base files. It's making our drawings incredibly slow and frustrating the entire team. We are way too far along to try and re-build new line work. Copying our likework out and wblocking have all resulted in these entities being carried through.
I ended up exporting the linework base file I had to a DXF file and then brought it back in. This allowed me to then purge all of the blocks I was unable to see or purge before. I'm not sure if that's the best way to do it, but nothing else was working. Luckily I didn't have to do something like that to a file that had any built in intelligence, it was just lines. Thanks for everyone's help.