Remove previously used format strings from drop down list?

Hi
How do I remove previously used format strings that MP3tag has remembered from the drop down list? I have lots that are useless I as entered them incorrectly.

Thanks

Next to such a list is usually a button with a right-arrow.
In the functions of the menu that opens if you click on that button there are some that deal with the deletion of one or all items from the list.

Thank You

I should have looked harder!

When the box has a format string you don't require you can also press SHIFT+DELETE to remove it.