while in the storage room look in the mirror. look very close at the mirror and you'll see a button with a sign that says "don't push!". walk over to the button and press it.(note: you can't see the button without looking at the mirror). after pressing the button the wall will go back and reveal a poster with a picture of a boo behind bars. use the vacuum cleaner to suck the poster off the wall and reveal a button. press that button and (spoiler) a bunch of boos will come out of a hole in the floor. professor e. gadd will tell you how to hunt them down. catch 5 boos and you'll get to go to the washroom and good luck from there on.