There exist several safe, environmental friendly and cheap solutions to remove lime scale from a toilet bowl. From chemistry’s point of view, every substance is classified as a chemical, but in everyday language the word is used as a synonym for toxic substances.
These harmful cleaning agents can be replaced with several safe and more efficient solutions.
Citric acid is the most efficient natural solution to remove lime scale. Scoop out as much water as possible from the toilet bowl. Boil up a pot of water and pour it into the toilet bowl. After that, pour in ½ cup of citric acid and leave it in the toilet bowl for 30 minutes or more. Use a toilet bowl brush to rub off the lime scale and then flush. If there is any more lime scale remaining, repeat the procedure.
If you don’t have citric acid, use vinegar. As before, remove as much water from the toilet bowl as you can and then pour in a cup of vinegar and leave it in overnight. Thoroughly brush the interior of the toilet bowl before flushing.
Because of its acidity, coke can be used to remove lime scale as well. Use a whole bottle of coke, pouring more on spots where the lime scale is deposited more thickly. Leave the coke the toilet bowl overnight and then brush.
Sometimes lime scale deposited over many years can be removed by no other solution than a mechanic one. Use an old and cheap knife that you can throw out after the procedure. Use rubber gloves, scoop out the water from the toilet bowl and you may start scraping. The advantage of the method is that the results are immediate, but the disadvantage is that you may scratch the toilet bowl. This is why you should use a knife only if the first three methods were not successful.