She will use it to remove the crayon marks on the kitchen door. When she is done with the kitchen door she will notice the black marks on the light switch. Next she will see the scuff marks on the kitchen floor that lead to the family room where she will wipe off the marks along the walls where the furniture has been pushed up against the wall. This will lead to the stairway and she will see the dirty banister and while wiping that on her way up the stairs she will see the bathroom, when she reaches the bathroom she will see the soap scum on the tub and will use what is left of the Magic eraser to wipe it down... then most likely she will plop down in a recliner and call the local pizza parlor and have them prepare dinner.
I love the series of books by Laura Joffe Numeroff, and when I was doing some cleaning today with my Magic Eraser, which I think is the best invention since sliced bread, I was hopping from one task to another and that story popped in my head.