I'm a long time user of CS and not a paid shill for Big Pharma. From what I'd read on the Silver List and the CS Yahoo Group many years ago, I was led to believe that at 20 PPM, it is simply not possible to get argyria. The scare stories all featured a small handful of individuals who took highly concentrated silver soups.
As it turns out, if you ingest enough properly made CS, you can get argyria. My argyria is quite mild, and it has faded a bit with time, possibly with help from chlorella, selenium, and Far Infrared Sauna . I had been fighting a chronic low grade infection and was drinking 1-3 12oz glasses of CS per day for several years.
My advice now is to not use it long term, if possible. And limit consumption to 6oz per day.
I am fortunate in that I still have my tonsils, and the other day, one of them swelled a bit and felt scratchy. That's my early warning system that I'm coming down with something, and I used CS for the first time in almost two years. I gargled and drank half a glass, and my tonsil was back to normal the next day. I'm still a huge fan of CS, but I now use it with great restraint.