How can I delete older revisions of a wiki

I recently started to use your Wiki plugin. I started a cat wiki (http://www.katz-wiki.de).

The “problem” I have is that I create so many revisions of just one wiki because I change the appearance, the font, the wording etc. Can I somehow delete some of the older revisions?

This is only for creating the wikis. I would like to keep the revisions once the look and feel of the wiki is fine.

Thanks in advance for your help,

Tina