Rub a soft, white eraser over the stain, applying gentle pressure. This may work if the stains in not too deep into the grain of the paper. The eraser skims off the top of the paper. Do not use a colored eraser.
Mix 1/2 tsp. of bleach with 1/4 cup water. Dip a sponge into the solution and dab the stain lightly if the eraser does not work effectively. Use care when applying the bleach to colored areas on the print. The bleach will fade whatever it touches.
Blot off the bleach mixture with paper towels. The goal is to allow the bleach to lighten the stain without saturating the paper. Once the stain fades, leave the print flat until it dries thoroughly.