My .metadata/.plugins directory currently consumes 6.2G. That's a "G", not an "M". That's utterly ridiculous - how does one clean it up?
It is problably the history files.
See CodeWarrior Tool Tip #3: History repeats itself and how to minimize the history size.
Alternatively, you can check/delete the history files here:
.metadata\.plugins\org.eclipse.core.resources\.history
Maybe this helps?