If you'd like to remove old or unused tags please follow the steps below. Note that removing tags this way will remove them from all contacts. If you'd like to remove tags by contact there is a separate article here to do that.
1. Go to the Contacts screen and select Delete Tags
2. Select the tags that you'd like to delete
3. Once you've selected your tags and clicked Delete you'll be taken to this screen to say that the request is being processed
4. Once the request has been processed the status will change to Complete. Click Back and you'll see that the tags have been removed.