Not all articles belong on the Warhammer 40,000 Wiki. Those that don't, either because they're spam or violate the guidelines set forth in Warhammer 40k: Content, need to be deleted.
These pages will most often be removed by administrative fiat after being identified as in non-compliance of wiki guidelines or quality standards by an Administrator or other editor.
Articles for Deletion
There is a Category Page titled "Category:Articles for Deletion" which contains a dynamically updated list of articles users have marked for deletion. The simple alternative is to click the link to report a problem page.
To add a page to this list, simply edit the offending article and add the following category tag to the bottom of the page to be deleted: [[Category:Articles for Deletion]]