5. Allow the product to sit for at least 15 minutes, or longer for heavy build-up. For particularly stubborn stains, you can leave the cleaner or vinegar to work overnight.
6. Scrub the bowl with a toilet brush. Focus on the stained areas and use firm, circular motions to help break up the deposits. A pumice stone can also be used for tough stains, but be sure to wet it first to avoid scratching the porcelain.
7. Check the results. If stains remain, repeat the application of cleaning product or vinegar, and scrub again. For persistent limescale, a combination of baking soda and vinegar can be used to create a fizzing action that helps to lift stains.
8. Once satisfied, turn the water valve back on. Flush the toilet several times to rinse away the cleaning product and any loosened limescale.
9. For maintenance, regularly clean your toilet bowl and consider using a water softening agent if you live in an area with hard water. This will help prevent limescale from forming in the future.

By following these steps, you can effectively remove thick limescale and hard water stains from your toilet, ensuring it remains clean, hygienic, and visually appealing. Regular maintenance and the occasional deep clean will keep limescale deposits from becoming a significant problem, saving you time and effort in the long run.