Delete cell styles in Excel 2007

You can delete the cell styles that are defined by Excel 2007 like Good, Bad, Neutral under the Good, Bad and Neutral but you cannot delete the Normal style. You can delete the styles that are under Data and Model, Titles and Headings, and Number Format. If you had defined a custom cell style then you can delete them. If you had formatted cell(s) using the Cell Styles and had deleted the style from the Cell Styles then the formatting applied to the cell(s) will be removed.
Perform the following to delete cell styles:
On the Home tab, in the Styles group, click Cell Styles. Right click any style and click Delete.

Note:
Once you delete an existing or custom cell style and saved the workbook. On closing and opening the workbook, the deleted styles will no longer appear. However, if you open a new workbook, all the predefined cell styles will appear but the custom styles will not appear as you had not created any custom cell styles in the new workbook.