I found the solution: go to https://v2.steemconnect.com/revoke/@appname and replace appname with whatever app you want to remove, like dtube.app or dmania.app. You can get the name from your steemd.com profile, letf side at the bottom of your info. It will show immediately on your profile, but you will still share profits for the next 7 days.
RE: How do I remove permissions from Dtube and Dmania?