Black on lid of corn
i pressure canned corn for my first time this year. Opened the lid to add it to stew today, black spots on the lid. It smelled and looked fine (other than being a bit brown but i think thats normal) and the lid was still sealed. I was scared and put the lid back on and threw it away but now googling I read about this 'soot' and wondering if thats what it was as it didn't appear fuzzy. The picture hopefully shows, the lighter part is where i scratched at it, it looked like the darker part before i touched it. Help, worried all of them will have this!