I ran into this in ACAD 2010 with some drawings exported from TurboCAD...7500 proxy objects (argh!). Saving as a DXF (R12) was an effective method for removing the objects.
Cheers!
Chris
I'm just an AutoCAD newbie, but when I exported to DXF R12, my file grew 10X, and when I saved it back as a DWG, it was still about 2X the original size. Not only that, but it got rid of some useful features I had in the file, also.
Why wouldn't just going to File... Save As and then select the "Tools" dropdown, then select Options... and uncheck "Save proxy images of custom objects" then save the file ???
It appears to have worked for me, and my file actually got a little smaller that time, instead of larger, and all of my other information is retained...