Sometimes with Excel formatting you just want to clear everything and start again from scratch. You can clear just the formats, and there is an icon you can add to the Quick Access Toolbar to make clearing all the formats earlier.
On the Home ribbon, on the far right, in the Editing section click the Clear drop down – image below.
Right click the Clear Formats option and choose Add to Quick Access Toolbar.
The icon below is added to the Quick Access Toolbar.
This will clear all the formatting, including conditional formats.