The answer to tough stains on sanitizing is to first identify the type of stain and use the appropriate cleaning method. Common causes of tough stains include dried-on food, grease, and mineral deposits. Symptoms include unsightly discoloration and lingering odors. Solutions can include pre-treating the area, using specialized cleaning products, and scrubbing with a stiff brush.
For DIY cleaning, try a mixture of warm water, vinegar, and baking soda. Let the solution sit for 15-20 minutes before scrubbing. For tougher stains or large areas, consider hiring a professional cleaning service that has access to more powerful equipment and cleaning agents.