Flash FLA file size becoming huge for no good reason

Q1: What is the reason for the enormass bloating of FLA file size, when many edits and saves are made to a FLA file, yet assets are not being added to the library?

Q2: What is the best technique to keep FLA files smaller in size? (with the problem described below. I am not talking about published SWF files or asset management)

Over many edits and many saves of my FLA files, they become 30 times the size on disk from where they start out. Example 750k can get as high as 34mb. In the past "save and compact" used to fill the role of reducing FLA file sizes but now that feature is gone.

The issue is discussed here but does not provide a satisfactory solution or reason:
http://www.xllusion.net/ed/2010/05/04/no-save-and-compact-on-flash-cs5/

Extra Details:

When I save as a CS4 file then back to CS5 the file becomes much smaller after it has become bloated, BUT I take a risk every time I do this that the file will become corrupted (I've had corruptions happen).

I have read that files which were created in CS5 and are never in the format of CS4 don't have this problem, but I find that theory unlikely since I have tried to follow this rule to no success.

I have also read that every FLA file tracks its "history" of assets. So adding and removing assets to the library will sometimes cause bloating because old assets that are removed from the library remain in the FLA file. This seems bogus because there is no purpose to this, but could be an indication of a bug in Adobe Flash Professional CS5, and CS5.5.

Personal details: the files I am editing contain personally created flash components, images, audio, many symbols (20+) but no embedded video.

For me personally, this bloating is a problem because I'm dealing with hundreds of flash FLA files that should be about 1-4mb in size but are instead much larger. The overall effect is that I end up with gigabytes of files instead of hundreds of mbs.

Thanks so much for your help!!!