There are several effective tricks to clean a toilet bowl. One of the best ways is to use a combination of baking soda and vinegar. First, pour a cup of baking soda into the toilet bowl and let it sit for several minutes. Then, pour a cup of vinegar into the bowl and let the mixture sit for about 10 minutes. Scrub the bowl with a toilet brush and then flush. The baking soda helps to scrub away stains and odors, while the vinegar acts as a natural disinfectant. Another trick is to use a pumice stone to scrub away hard water stains and rust buildup, but be sure to wet the stone and the toilet bowl first to prevent scratching.