Games can only be archived, but will only be deleted automatically two weeks after the game has finished.
  1. Go to your Games
  2. Click on the game you would like to remove in the list.
  3. Click on the preview image or "i" icon of the game that is displayed on the right side.
  4. Click on the Folder button. This will move the game to your archive.
Now you can keep your active games neat and tidy!