How to delete a Class

Hi, sorry the repost. I follow the instructions for creating a class, like http://www.xwiki.com/xwiki/bin/view/XWiki/FAQClass?language=en How can i delete this class? Also, anybody knows why this documents are not indexed by the lucene plugin ? Please, thanks. -- A.U.S. Enrique Ferreyra Centro de Cómputos Red Megatone - Red Confina