I know what you mean about the sooty mold (I also get that on leaves sometimes). But what I am talking about and what I think is on Cablegirl's leaves is permanent damage that you can see and feel. It is rough or hard, sometimes the larger areas have actual lumps inside the leaf. It isn't going to go away. It is like a scar.
I understand. There was a reply that talked about wiping off the black. That is sooty mold. The permanent black scars are sunburn and aren't going away unless you cut the leaf off. Regards.