What is the name of the yellow powder?!

What is the name of the yellow powder?

that the old timers have used for deep hole wounds or what can be used on deep hole wounds''

You are probably talking about Sulfur.
Hopefully though you arent planning on using it.
It was a fix for the era that those "old timers" were in, but now there are better fixes.

Sulfur would be put on wounds and it would acts as a barrier, but the results wouldnt be nice. You would be left with a closed wound, but a scar that is just as bad. For instance, if you had a hole in your arm say 1/2 inch deep, you would end up with a scar that looked just like that, a hole. It just wouldnt be bleeding or open for infection. The wound needs oxygen and the sulfur would block oxygen and proper tissue growth, but it would protect the wound.

Now, another thing that it was used for was for serious wounds. Started during the World War, if someone was to come in to the "make shift" hospital with an arm or leg that had been severed, the medics would pour sulfur over it and strike a match. It would burn the wound cauterizing the vessels in the process, and in turn saving the persons life.

Sulfur is also a laxative, yet there again I can say there are alot better ways for you to medicinally empty your bowels.

Sulfur has gone out of use, because it is no longer good as a medicine. Again, there are many other better treatments out there

Hope this helps