AutoCAD blocks to grey

I would like a script that opens each block in an AutoCAD drawing then uses "Control A" to select all, then change the colour property to "ByLayer" for all obje and to check for Hatch and set the "Transparency" in "Properties" to 85%. Then "Control A" again and run the AutoCAD function "Overkill". Save the Block exit the Block and go onto the next Block. Save the file after every 10 Blocks.