This is an unfortunate limitation right now. However, those components won't get compiled into the final SWF, so they won't bloat it. Look for this feature in future releases.
Ok, and when if i import the project in Flash Builder......
Will that be bloated and in need of some clean-up?
When you import the project into Flash Builder, the components will still be in the project, but they also won't get built into the swf if they are unused.