Why not just do one on Hmong Shaman in particular...
That is nigh impossible. Most skeptic will brush it off. Because first of all to get a skeptic attention, you must have physical proof to the naked eye.
For example in a Trance: The skeptic want to see if there is any peculiar change towards a shaman. Their temperature, blood pressure and etc.
Another maybe popular skepticism is the knowledge of the shaman. Of how they know other people past events. Is it staged? Or is it extraterrestri
al.
As for incense and altar, skepticism must control to see if there is any tempering.