I started out mixing Lugols 5% with water and applying to the scalp, and that worked well, except for the staining. Dandruff just vanished!
Now I apply SSKI directly to the scalp (no water) using the eyedropper and this is much better. No staining b/c SSKI is clear, and just one application zaps dandruff for many months.
I also spray SSKI (full strength) on toenails to kill toenail fungus once a month.