MegaGlest:Always assume good faith
Always assume that ANY edit made to the wiki was for the good of the wiki, which we value above anything. Just because an edit is out of place and disorganized, actually worsening the article it was meant to improve does not make the edit 'spam'. We must always assume that all edits to the wiki are done with the geniune wish to improve the wiki.
Not everyone starts out strong
Remember that the wiki often has new users make edits, and those users may not be well versed with the ways of the wiki or its expectations in quality. However, that doesn't mean that they can't be a useful editor. Nobody begins as an expert in something, and has to learn from somewhere, so rather than yelling or getting mad at the users, politely inform them of their mistakes and take steps so that in the future, their edits can have even more impact!
You should consider pointing the new user to the Policies of the wiki, in particular, the style guide.
Don't remove, but improve
Those good-faith edits often contain useful data to the wiki, even if badly formatted or incorrectly placed. Rather than rolling back the user's edit, be bold and improve it so that the information may be used by the wiki.