A world with superheroes and supervillians is bound to get messy. Aliens bleed. Capes get messed up. Utility belts get rusty. And let's not get started on the sweat that pools in the deepest recesses of spandex and leather suits. Most superpowered beings are exactly like you and I: they have no time (or patience) to scrub radioactive gunk off their gloves, so they require specialized services. Your regular Chinese Laundromat is not equipped to handle that kind of stuff, so when in need the superbeings turn to ... Atomic Laundromat.
The Laundromat is like Friend's Central Perk. Like the bar in Cheers. Like the random restaurant in Seinfeld. Like the Hall of Justice in Superfriends. Except with more smelly underwear all over the place.