Once the AddIn is loaded it adds a Remove Styles
button to the Home Ribbon to the right of the Styles gallery. Open the workbook which you want to remove the custom styles from and click the
button. The AddIn will remove all Styles that are not built-in styles for Excel. If a Style has an invalid name the AddIn may not be able to remove it, you may be able to remove these manually in the Styles gallery.
For more information about removing styles to help avoid the Too many different cell formats
alert see the following KB article
You receive a "Too many different cell formats" error message in Excel