Image Recognition - stop tracking image

What's the latest on stopping the tracking of an image? All I'm trying to do is have a Clear button that basically resets all tracking. So if you pointed your phone at too many images and have too many 3D figures being tracked, you can press Clear and all the 3D figures go away. Then you can point your phone at some of the images again and start tracking them again.

I've tried clearing the list of visualizers, I've tried making TrackingState set-able for Images so I can set it to Stopped, but it's not working. Seems that I can't get rid of the anchor or something.

Am I missing something obvious? I literally just want to press a button and have a clean slate...

Thanks