Knowing how to clean a glass shower door will keep your bathroom looking pristine. Shower doors can quickly be marred by unsightly water marks from everyday use. As residual water dries on the surface, it leaves behind white calcium carbonate deposits. Ventilating and wiping out the shower promptly can stop these marks from forming, but even with great care, some will always slip through. And once they do, they’re a real nuisance to remove.