Citric acid is a white crystalline substance with chemical formula C6H8O7. It occurs naturally in some fruits, but in particularly high quantities in lemons and limes. It is used in the production of foods and drinks as well as in the cosmetic industries, however it is also a very effective cleaning agent. Citric acid is an excellent limescale remover and also a natural bleaching agent, so it is a valuable item to have in your cleaning collection.
How to use citric acid
When bicarbonate soda and vinegar are not up to the task, you can bring out the big guns and use citric acid.
Toilet: Just before you go to bed add a 1/2 cup of citric acid and 1/2 cup vinegar to the toilet bowl. Time will be your friend, so just leave it until the next day. If there has been a lot of lime buildup you may have to do this a number of times.
Shower head and taps: Dissolve 1/4 cup citric acid into 2 cups vinegar and spray on to the limescale. Leave it for a while, then wipe clean. If there is a thick build up you may have to apply a number of times. When cleaning taps, wrap them in toilet paper and then soak the paper with your citric acid and vinegar solution. This will allow the solution to soak into and dissolve the limescale. If you have a particularly difficult shower head, fill a sturdy plastic bad (with no holes) with the mixture, and then immerse the shower head into the bag and secure in place with an elastic band. This will allow the shower to soak in the mixture.
There are a number of things you can do with this fantastically versatile ingredient, such as making your dishwasher tabs, or natural toilet bombs. Both put citric acid to great use.