As to the danger of handling arsenic.
Here in The Land of Oz (AKA: Australia), people who need to work with arsenic are routinely tested for arsenic levels in their body and appropriate action is taken.
In Jawa I have known a number of people who stain blades, some use the commercial method that the video shows us, or a variation thereof, others use the method I have set forth, or a variation thereof. None have been affected by, nor died of arsenic related diseases, most have died of emphysema or some other tobacco related disease.
Yes, there can be no question that arsenic can affect health. It is a possibility that depends upon the level of exposure. In many parts of the world, arsenic used to be used as a medication.
The easy availability of knowledge that has arisen since the proliferation of the internet is very tempting. The making of a video now is common. The big, very big, problem with this internet knowledge is that we need a very strong foundation of real knowledge to differentiate between true knowledge and waffle.
There is one hell of a lot of waffle on the net, and You Tube is a major offender. I sometimes think it is an intentional disinformation campaign to dumb everybody down to a pre-determined level. A tool of societal management.
The method that I have outlined above does work. Results can be improved by using slight variations, variations that I myself use, but that I am not prepared to recommend to others because of the possibility of somebody taking legal action against me.
I stained a lot of blades very successfully before I ever learnt the variations used in Central Jawa.
Some years ago I spent a day or so with a lady who worked in the museum industry, I ran her through the entire process of staining and when we parted she had a very good understanding of the process. My contribution was only a small part of the further research that she carried out. Eventually she produced an academic paper:-
Scroll down to page #19
https://aiccm.org.au/wp-content/uplo...June2007_0.pdf