I have a really crazy tip for you today: Did you know that people in early days used bread to erase pencil drawings? You can do this too, it's very easy! Just take the soft interior part of the bread (not the crust) and knead it like clay until it becomes a tight little white ball. Write something and try it out! This works just with pencil drawings of course.
So the next time when you don't have an eraser but a piece of bread, you know what to do :)