Clean up Winsxs on Windows 2008 R2 after SP1 Install

The procedure is the following:

  *Install Windows Service Pack 1 then ...
  *Start and elevated command prompt (run 'CMD' as administrator) and ...
  *Run the DISM command, which replaces the old VSP1CLN and COMPCLN we used on previous Windows versions: DISM.exe /online /Cleanup-Image /spsuperseded
  *Wait 10 minutes before the task completes (it ends with "Service Pack Cleanup operation completed. The operation completed successfully")

Normally you should have been able to reduce the Winsxs folder size by 1 or maybe 2 GBs, sometimes more. Saved space may vary a lot.