There’s a reason mustard and curry stains are some of the toughest to get out! They are considered a pigment stain – a naturally occurring color that is not water soluble and therefore cannot be removed with normal cleaning.
CAUTION: The process used to remove pigment stains is the most aggressive stain removal process and has the great possibility of removing the dyes used to color the carpet fibers during the manufacturing process. There is a great risk of removing or bleaching the color of the carpet fibers.