You may be surprised to learn that I do know the difference between perchlorate and persulphate. My point, and question, is that you have not given any reason why Ammonium Persulphate is not preferable over Ferric Chloride. You claim the high ground on chemistry but have to resort to questioning my reading ability! BTW, what illegal activity am I encouraging?
Yes, I'm surprised. Maybe you can tell me how perchlorate works as a copper etchant for PCB, then.
As for the illegal activity I more than alluded to, but which seems to have somehow eluded you -- it varies from place to place, but purposely dumping concentrated toxic chemicals and heavy metal compounds down the drain, in the storm drain, or on the ground is illegal in my part of the world. Thankfully so, but for the few who choose to flout the law and common sense.