Remove styles in post

Hello,

I run a news blog, and work with several contributors.
Each one of them sends articles everyday, and I upload them automatically with postie plugin (mail to post) or manually.
The problem is that each contributor sends the content with a different style and format in the text, and I always need to clean it back to my site style, which is not always easy and take me a lot of time.

Is there a way or plugin which does it automatically?

10x!