title: How should the sstate-cache directory be deleted in Yocto?
body: <p>The size of my <code>sstate-cache</code> directory of my YoctoProject "fido" environment is more than 3GB.
  How can I delete the <code>sstate-cache</code> directory in <code>yocto/build-dir</code>?</p>
  
  <p>Is it save to use <code>rm -rf</code> or is there any other method?</p>