ChildOfMaroon

I know this is theoretical, but I am super interested in how the two would affect each other. Any theories would be appreciated.

I am trying to figure out which chemicals/compounds might cause mild chemical burns in liquid form. I am not necessarily interested in things which would cause severe burns like acid; rather, I am interested in things which would give mild burns to human skin, perhaps after prolonged exposure. I was also interested, primarily, in organic chemicals which arise naturally in nature and not things which are synthesized, but I understand that might not be possible. Any help would be much appreciated. Thanks!