That's the key word and what makes the difference - "damaged ...". If Joe Sixpack, coin collector, can - use the word of your choice - clean/conserve a coin and have the end result be the same as if NCS does it - then no, most will not consider this coin harshly cleaned. Yes, cleaned it will be, of that there is no question, regardless of who does it. But will it be harshly cleaned so that the surfaces of the coin are damaged ? But that's the problem isn't it. The average collector cannot clean a coin without damaging the surfaces. NCS can in many cases.
I wish I knew how they did it...I bet they use something that wouldn't be liked too much in the hobby... Speedy
I would speculate that the coins are dipped in the same stuff everyone else uses but probably at a diluted concentration and for a very short period of time.