Rust Out Sour manufactured by Diamond Products is a premium sour designed to eliminate any residual alkalinity in the final rinse water. This results in taking the harshness out of your fabrics. You’re left with soft, comfortable sheets, pillow cases, or any other linens. Rust Out Sour has the added benefit of being formulated to remove yellowing and rust deposits caused by high iron content. This is especially important in areas that have high levels of iron in their water.