Problem scenario
In a pre-boot menu on your server/desktop/laptop, there is a UEFI/BIOS screen showing a "boot menu" with vestiges of older operating systems that used to be installed. You do not want these displayed because many are corrupt or otherwise deleted. How do you remove the options from the menu?
Possible Solution #1
If you are using Linux, install efibootmgr. Run the efibootmgr command utility to delete the old OSes.
Possible Solution #2
Log into BIOS/UEFI and edit the boot order. There should be an option to delete the ones you see or otherwise prevent them from showing.
Possible Solution #3
Is there a secure drive wipe feature or "factory reset" ability in your BIOS/UEFI (pre-boot menus)? (Sometimes it is entered by pressing F11 during boot up (for some HP and Lenovo machines). Sometimes it is entered at the OS level for some Dell machines.)