Wikis can be removed by deleting specific folders on the file system.
For example, to remove Simple Wikipedia.
- Delete the wiki directory under C:\xowa\wiki\simple.wikipedia.org
- Delete the css directory under C:\xowa\user\anonymous\wiki\simple.wikipedia.org
- Delete the files directory under C:\xowa\file\simple.wikipedia.org
Note that there may also be images in your commons directory which can only be removed by deleting the entire directory: C:\xowa\file\commons.wikimedia.org
For example, if you have viewed the Earth article in Simple Wikipedia you will have downloaded the The Earth seen from Apollo 17.jpg to C:\xowa\file\commons.wikimedia.org not to C:\xowa\file\simple.wikipedia.org. Note that commons is the destination because the actual online url for the image is https://commons.wikimedia.org/wiki/File:The Earth seen from Apollo 17.jpg.