Wow. I'm not sure.....
Someone will be along tho.
I've seen it suggested to rub a crushed vitamin c tablet on the stain and if it fades, the stains are metal. Also with a chlorine puck, let it sit on the stain and if it fades, the stain is organic.
Hopefully if there is another suggestion for you someone will chime in.....
Welcome to TFP!