Good question, but not everything may be as it may first seem to be !
One of the Natural forms of Iodine is in the form of Calcium Iodate, it is very Alkalizing !
Iodine may be very Alkalizing in one of it's Isotopes ?
And because the body only needs a very small amount of iodine to function properly and it must have this in a Complex with other Alkaline Minerals in order for the body to utilize it properly without overdosing on it, it may have the potential for easy Poisoning in the elemental form !
Now consider that most people may be Sick and Diseased because they are too Acidic !
Then consider what a very powerful Alkalizing agent as elemental Iodine may do to change the pH of the body ?
And as long as the body has enough other Alkaline Minerals for this Paint of Iodine to combine with, one may feel an immediate change in feeling upon taking some as a paint, because this combination may Cause Neutralization of Acids in the area painted ?
As to the idea that if the paint dissappears by the next morning meaning that the body is Low of Iodine, this question may be so or not so depending upon other conditions !
For this may depend upon how Acidic the skin may be, for if the skin is more to the Alkaline side as it should be, then this iodine test would not show the same Results as if the skin was more Acidic !
But , as many people are short of Iodine in the First place, then many people may see some improvement in the beginning, but when they continue to make use of it as some are talking about, this may lead to Poisoning ?
As some may have already experienced from Headaches etc , yet they are trying to convince themself and others that it is just a Detox reaction from other things !
I call this kind of mind set , to be like the ostrich with his head in the sand, thinking he is hiding from everyone !
There is a Reason that Iodine is a "Trace" element, it may be because the body only needs a small Trace of it and this may be Best with the other needed Alkaline Minerals !
For when one uses Kelp, one does not need to worry about Poisoning from an overdose of Iodine !
"WHY" would anyone with any "Common Sense" want to take something which may Poison them by an overdose ?
Especially if one has children in the house, they could easily become Poisoned from a vial of Iodine by ingesting it !
Do some people have no more care for their Families so as to keep Poison in the house ?
Of course if people are "ONLY" concerned about themself Mentality and to Hell with everyone else, I guess it does not matter to them how much Poison they keep around ?
One may get all the needed iodine from good quality Kelp and also get all the other needed Alkaline Minerals as a Bonus, what more could a person with Common Sense want ?
I would like to see those Promoting the use of Elemental Iodine to put up a Million Dollars or more to cover the Liability of it !
In other words put their Money where their mouth is and see how long they stay around !
Smile Tis your choice.