And more! Bought a house built in 1951 and the guest bathtub, porcelain, is pretty bad. It had brownish-rust colored stain all around (like a ring) but also top-to-bottom brown/rust-like stain around the front of the tub and drain. Borax hasn't budged it; neither has baking soda/vinegar. Any ideas for cleaning this out of the tub? Also, is there any hope for grout that is really old and pretty much brown from caked in dirt? The bathroom floor has neat older tile but the grout is so dark it looks gross. Any ideas? TIA!