If your toilet bowl is stained you can try cleaning it while you sleep! Simply pour one cup of white vinegar into the bowl. Drop in one denture tablet. Go to bed. In the morning flush to reveal a clean bowl. If it was very dirty you may need to swipe it a bit with a toilet brush. The acids in the vinegar will have broken down the grime and mineral deposits while the chemical oxidants in the denture tablet will have removed stains as well as prevent germs from spreading.