Go to the Privacy tab on one of the profiles and scroll down to the Trusted List section.
If you don't want to manage them but still want to be on the trusted list, click the "Remove as manager" link to the right of your name.
If you want to remove the profiles entirely from your Watchlist, click the "Remove Yourself" box below the list of people on the trusted list. That'll both take you off the trusted list and remove you as manager.
If there's more than a handful of profiles you no longer want to manage, you can use the Bulk Trusted List Changes page to select the profiles and remove yourself from all of them at once; that's usually a little faster than removing yourself from one profile at a time.