Citric acid naturally occurs in citrus fruits like lemons, limes and oranges, but it's also added to a variety of food and beauty products to inhibit mold and bacteria growth for a longer shelf life. This bacteria-killing property makes a citric acid cleaner a nice disinfectant for your home, but the acidic nature of this compound also makes it effective at lifting stubborn rust and limescale from a variety of surfaces around your home.
Take Some Safety Precautions
Don't be fooled into thinking citric acid cleaner is completely harmless by the fact that you regularly consume small amounts of citric acid thanks to its prevalence as a food preservative. This compound is powerful in its concentrated form, which is how you buy citric acid for cleaning.
According to Global Safety Management, citric acid should be kept away from the skin and eyes, so wear gloves when using citric acid in any form and wash your hands after use as an extra precaution. Wear eye protection if using it as a spray cleaner, especially if there are open windows or fans moving air through your home. Keep both the concentrated citric acid powder and the diluted cleaning solution out of reach of pets and children.
Clearly label the spray bottle or container where you store the cleaning solution so that it doesn't get mistaken for water or mixed with other cleaning chemicals, which is never a good idea due to the risk of a dangerous chemical reaction. Citric acid should also be kept away from heat sources or open flames.
Making Citric Acid Cleaner
Buy pure citric acid as a powder from your preferred supplier. If you find citric acid conveniently sold in 2 oz. packets, you'll have a particularly easy time using it to create a homemade cleaner. Two ounces of citric acid (about 1/3 of a cup) dissolved into 1 gallon of warm water will produce an ideal concentration for removing typical build-up from surfaces around the home.
You can reuse an old gallon milk jug for accurate measurement but be sure to label the jug as "poison" and to store it out of reach of children to prevent accidental ingestion. Fill the jug about halfway with warm or hot water from the tap. Use a funnel to carefully pour in 2 oz. citric acid, and then continue to fill up the rest of the jug with warm or hot water. Twist the cap into place and shake the mixture to thoroughly dissolve the citric acid.
Then, you can pour the cleaning solution into a mop bucket for cleaning floors or into a spray bottle for cleaning counters, sinks, faucets, etc. Do not use citric acid cleaner on surfaces that may suffer damage from acid exposure, such as marble or natural stone.
Using Stainless Steel Acid Cleaner
Citric acid is particularly useful for cleaning rust, limescale and other buildup from the stainless steel fixtures around your home. Spray the citric acid solution directly onto the dirty stainless steel and let it soak for several minutes. Then wipe the surface with a dry cloth. Rinse the surface with water and dry it again.
If some debris remains on the stainless steel, repeat the process and add in a little elbow grease after letting the second round of citric acid soak in. It should lift right up!