The answer to 'tough stains on countertop' is to first identify the type of stain and then use the appropriate cleaning method. Common causes of tough stains include spills of acidic liquids, oil, grease, or food. Symptoms may include discoloration, etching, or a sticky residue that won't come off with regular cleaning.
For DIY solutions, try using a mild abrasive cleaner, baking soda and water paste, or a degreasing agent like vinegar or lemon juice. Apply the cleaner, let it sit for a few minutes, then scrub with a soft-bristle brush or sponge. If the stain persists, you may need to call in a professional cleaning service that can use more heavy-duty techniques like steam cleaning or specialized solvents.