I have always used offhand grinding for my tungsten sharpening. The only time I didn't was when I got curious about a chemical system for sharpening tungstens that I used back in the early 1980's. I don't remember what the stuff was called but it was used by heating the tungsten and dipping it in to the chemical until the desired point was achieved. It was useful at times but it was more trouble than it was worth as it appeared to contaminate the tungsten with some of it's constituent components. It also never really got the tungsten as sharp as I like mine. It didn't have the drawbacks of conventional grinding, but it came with it's own complicated baggage that made it more of a novelty than a useful tool for me. This is only my opinion and does not reflect poorly on the product.
I think one of your contributors also commented on this product. He calls it Chem-Sharp and if my memory serves me right, I think this is what I used as well.
I am sure there are several different makers of the product, but what I have used is called Chem Sharp.
The fumes are what I hate. along with the residue that it leaves on the tungsten.
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