Deleting links to GPOs is the more common task that you will be accomplishing. It is quite common that there are many more links inside an Active Directory domain than there are GPOs, because one GPO can be linked to many different places. The process for rolling out that GPO setting along with its links was probably an extended affair, starting with the creation of the GPO itself, moving on to testing those GPO settings by linking to test OUs, finalized by creating links to production OUs inside your environment in order to start pushing the settings to production computers. The reverse is generally the smart way to go when removing settings. It is most common to delete the links to the GPOs before you delete the GPOs themselves. This retains the GPO and all settings inside the GPO, so that you can reverse ship if needed and re-link those GPOs in the event that the link deletions start to cause problems.

Deleting GPO links is very simple: you right-click on the link and choose Delete. However, it is super important to make sure that you are deleting the link, and not the GPO itself. In the following screenshot, you can see the GPO called Set Wallpaper to Unicorns listed under Group Policy Objects, and you can also see the link to that same GPO listed under the IT Department OU. You could easily delete either thing inside GPMC, but you only want to delete the link. The icon for links always has the little arrow on top of the scroll. There aren't any links that show up underneath the Group Policy Objects folder, so make sure you are not deleting something down there. Instead, we are right-clicking on the link that is hooked to the IT Department OU, and choosing that Delete function: