Help TinyMCE on MODx Evolution messing up HTML

Hi,

We are currently working on a site and have been asked to clean up the all the MODx pages 2,000 of them as over time from when users have been editing the pages TinyMCE has been messing up the formatting adding <span tags and x-small tags all over the place.

As a test I have just cleaned a MODx page and removed all the span tags with no editor selected, and when I switch back to TinyMCE editor the html is fine.

However when I go to edit the content for example create a bullet list the horrible span tags are being applied again.

Does anyone know how to stop this from happening? And any tips for cleaning 2,000+ pages would be great also?

Thanks Aaron