The Magic Eraser (Locker 37, Bk. 1)

Carson Cooper realizes that he has a very inconveniently located stain on his pants. That is NOT the way to start things off on the first day of school. Fortunately, Carson finds a letter written by last year's fourth graders stuck to the bottom of his desk with some watermelon bubble gum. The note explains the existence of Locker 37, which will provide a solution to any problem! And when Carson sneaks off to the locker it does, indeed, provide a solution--an eraser! But the problem is that the eraser works a little too well, erasing anything it's rubbed against three times. ANYTHING.