Characteristic postmortem finding of carbolic acid poisoning is
Stomach mucosa :

Sulphuric acid : Charred / Black  / blottin paper stomach
Copper sulphate : Bluish green
Ferrous sulphate : Green
Arsenic : pink velvety mucosa / strawberry
Nitric acid : yellow
Carbolic acid : White leathery stomach.
Grunish stomach
Yellow charred stomach
Brown leathery stomoch
Black charred stomach