Are plastic soup dishes safe to use if yellow stains are visible?
Plastic stains very easily. Anything tomato based or acidic can stain plastic and it is not harmful to you.
How do you get yellow age stains off of plastic appliances such as food processors toasters or blenders?
No, but they do make orange, and I can tell you how to make a yellow, and very easy. First. Get any old plastic Lightsaber Second. Put plastic over what you hold the lightsaber Third. Get yellow spray paint and spray the uncovered part, make sure it's a plastic like yellow. Fourth. Let it dry and then you got a yellow lightsaber.