OOOH, i know great remedies for this..
First of all, never put anything with tomato sauce in a plastic container as the plastic is porous enough to actually absorb some of the oils. Also, never use tomato sauce in anything with scratches in it.. like, a container that you used a steel scrubbie in.
If you must use it in plastic, when you go to clean it, slightly dampen the sponge/rag/whatever and put straight dish soap in the container and scrub vigorously with just the soap and the tiny bit of water. for some reason, this helps to pull out the oils. Also, try to clean the dish immediately after you're done using (as you should with any dish, but we all know that that doesnt always happen *looks at sink and sees a pile of dishes*)