Coffee grounds! Add a drop of grease-cutting dish detergent to a handful (about one-quarter cup) of used grounds, and scrub away at the tomato-sauce stains until all is clear. The coffee grounds absorb and neutralize the grease and tomato color better than a sponge or scrubber can (they just smear the sauce around). After you scrub away the stain and grease, thoroughly wash out your container with warm water and all traces of tomato stain should be gone.
More help in the kitchen…