Yes, I quite agree (with your take on Harold's take)
But there's a difference in perspective: Harold, as I understand from his posts, worked his operation as an ongoing business with a real location, where he knew that next week and next month and next year he would be getting more and more raw material to process/refine and thus could accumulate residues over longish periods of time in order to maximize yields of stuff he wasn't particularly trying for in the first place. He could also (in the era he worked) buy 55 gal drums of nitric acid as a matter of a simple commercial purchase. I am in neither of those positions. I am an acquirer, an accumulator of silver (and/or gold) without any particular desire to be a refiner, UNLESS refining can be done on a cost-neutral and hazard-neutral basis. My work, heh, I'll throw that in for free. My vision, my lungs, those are irreplaceable.
Right now, today, I am 98% silver and 2% gold. I can send marked sterling to any of several refiners and get back about 80% of spot in gross weight back in cash. I'm in no particular hurry to do so, as I prefer silver to dollars. Though I *do* like to sell off a kilo or two two now and then. No muss, no fuss, no chemical costs nor hazards, no protective gear, etc; etc; No skill or acumen, either, other than the skill of not overpaying for the raw materials. My costs consist of a scale which I already own and packing tape to seal the carton in which I send the goods away. I am perfectly OK with the idea that he who runs and fuels a genuine OSHA-compliant furnace (that I don't have) and an assaying operation (that I don't have) needs to make money from same. The thing that bugs me about this is that as the price of silver rises, the "refiner's cut" has risen to what I now consider a galling level. When silver was $11 and I lost $2.20/tr oz to the refiner, well, that was fairly OK. I had to buy and land a 46 gram sterling fork = 36.8 grams net .999 Ag (using the 80% factor) = 1.18 tr oz Ag * $11 for less than $13. Simple. I can either buy or not buy what I find. When silver was $15, 46 gms * .8 = 38.6 net grams = 1.18 tr oz Ag * $15 = I could pay no more than $17.70.
With silver now above $35, I am paying $7 per troy ounce for refining. It's the same old 20% but it's quite a bit more money. Sure, the refiners' costs have risen, but they have not tripled. So, this is my motivation behind investigating refining. You can sometimes buy silver for a buck or two under spot, but you're not going to buy silver for $7 under spot from anyone with functioning neurons.
Hence, as I see it, the feasibility of obtaining silver this way (by buying scrap sterling) has effectively ended. When I can buy known-mint .999 ingots for $1.50 over spot (a 4% premium) as hard as it is to buy $38 silver for one who has been buying it since $6, it seems dumb to do the scrounging to find cheap sterling which has a "penalty" of greater than 10%. If I could refine silver for under $3 a tr oz, then I would consider that route and that is why I am here. The few grams of Pt or Au I might get in the form of vile residual liquids have value, sure. But that exercise for me, a backyard guy, seems not particularly worth it. For a professional refiner, whole different story.