Cannot Decrease Size of File

[bt1101011]

Folks, we're having problems with some of our drawing sizes. We produce a 2d reflected ceiling plan which we send to our CAD duct brothers to 3dmorpholize into a model(they xref in our drawing and model over it, basically).
The CAD duct models are now corrupting and they are blaming our drawings. We are running standard Autocad 2012 (minus Service Pack 2, waiting on IT to ok that) We've done the usual, overkill, purge, checked for 3d, removed scales, removed unused layers. Tried exploding everything as a last resort and and overkilling purging etc again and that didnt work either. Exporting to dxf results in a 92 meg file, using -exporttoautocad crashes my machine. We need to pinpoint the problem to prevent it happening to our other files.
I've attached a link to one of the files any advice is much appreciated.

http://wikisend.com/download/264102/X-ME-ZC-01-332-WIP-RCP_02.dwg

[scott.wilcox]

Perhaps you can select all the objects in model space and wblock it out to a new drawing. Since your data is XREFed only, the layouts should not be necessary.

[arshiel88]

+1 on wblock. There's a lot of doors and texts on hidden layers in the lower left portion of the drawing. After WBLOCK and resetting annotation scales, your 8.5mb drawing is down to 237kb.