Dynamic blocks and file size

[Grendel]

I've been having problems with the drawing files I've been working with becoming too large. Our normal file size for a drawing is around 300kb. Lately, my drawings file sizes have been around 3mb.

 

My initial thought was that it must have something to do with the new dynamic blocks I had created and were using. When I got to looking into it, this is what I found. Whenever I insert a dynamic block and use its parameters to alter it, its associated block name is changed to something generic, such as *U312. This doesn't show under properties, or in the block list for the drawing, but it can be seen when trying to use the Filter command to select the blocks, or when purging deleted blocks from the drawing. The Filter command is what first clued me in to this. I was trying to grab all of a specific block by block name, and it wouldn't work. It would only grab the ones that hadn't been altered after being inserted.

 

So, I believe each of these instances of the block variations is causing my drawing files to become larger. Is there any way to prevent this, aside from bursting the blocks and purging?