You'll need two cans of Coke for this toilet cleaning hack - one for you and one for the toilet. Turns out, Coco Cola has carbonic acid, which can help dissolve calcium buildup and rust stains. This isn't going to replace your normal cleaning or be a miracle worker, but it's a refreshing way to get at those tough stains.
Pour one can of Coke around the inside of the toilet bowl, just under the rim, and let it run down into the water. Then take the second can of Coke and go do something else for an hour (we won't tell if you add rum, though it probably wouldn't do anything for the toilet). Come back and flush to see the stain is reduced.
Quick Tip
You can also use a pumice stone soaked in hot water for a hands-on approach to scrubbing off mineral buildup and stains, but if you ask us, we'd rather try the Coke and give ourselves a pedicure with the pumice stone instead.