title: What does the -clean parameter mean in the Eclipse IDE?
body: <p>I have read that after installing some Eclipse plugins manually, one should use the <strong><code>-clean</code></strong> parameter to start Eclipse. Why or what does it do? </p>
  
  <p>Do I have to do something else? </p>
  
  <p>This question applies to Eclipse Galileo and Helios, in particular.</p>