Lay the fabric flat on a surface. If the fabric has two sides, such as an item of clothing, insert a piece of cardboard between the sides to stop color dye from bleeding onto the other side of the fabric.
Fill in the spot with a fabric marker in a matching color. Follow the same direction when coloring the stain so the color saturation is as even as possible. Hold the marker gently over the surface when drawing to avoid heavy dye spots at points of pressure. If the stains are small enough to be covered with the fabric marker dye, no further action needs to be taken.
Mix colored dye with hot water in a tub and soak the fabric for at least one hour. Rinse and repeat as needed. This will help blend the colors to hide the stain. Filling in bleached stains with the fabric marker before dyeing prevents an uneven finish.
Launder the fabric or garment as normal.