Do you have old themes still installed on your website that you would like to delete? It is very easy to get rid of them and that is what I will describe below. It makes no sense to keep more than one theme installed on your website unless of course you have a test website.
To delete your unwanted themes you must access the theme’s Details section again. Mouse over the theme and click on Theme Details, see above image. This will bring up the Details section of your currently installed themes, see below image. Just click on Delete in the lower right corner.
NOTE: The delete option will never be available for your activated theme until you have activated another. ALSO, I want to clarify that an installed theme is not activated. A theme does not become visible until after activation.
Prior to fully deleting the theme, you will be asked to verify if you truly want to delete the selected theme template. Just click on OK and the theme will be deleted from your Themes page, see below image.
NEXT UP = Accessing and Updating Theme Options