Cleaning with Citric Acid? Here’s What You Need to Know.

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Citric Acid is a common ingredient that is found in a wide variety of consumer products, including cleaning products, food, etc. Besides its many uses as an ingredient, it can also be very useful on its own for certain cleaning applications. It is found naturally in citrus fruit juices (E.g. lemon juice) and is also available in dry crystal form. If you’re thinking about cleaning with Citric Acid, here are some things you need to know.

Should I Use Citric Acid?

Citric Acid is a mild organic acid. As a cleaner, it is very effective and appropriate to use for light descaling, removal of hard water stains, mineral deposits, etc. Some areas where a Citric Acid solution may be useful are: bathrooms, toilets, toilet tanks, kitchens, coffee machines, kettles, dehumidifiers, etc. Since it is a natural product that is relatively mild and safe to use, it may be preferred over more aggressive chemicals for cleaning. However, because it is relatively weak, it does have some limitations. For example, if you are confronted with major scale buildup or mineral deposits, Citric Acid likely won’t be too effective.

Other cleaning projects too tough for Citric to tackle? This mild organic acid doesn’t function well as a degreaser when used on its own (Grease and grime would be better removed with a basic product). While it may help lighten stains by pulling minerals into solution, it isn’t going to function well as a stain remover or bleach substitute. It’s also not a great rust removal product when used on its own, especially if there is a lot of rust. In addition, Citric Acid may have some antibacterial/antifungal properties, but it is not a registered disinfectant or fungicide, and shouldn’t really be regarded as such.

How To Clean With Citric Acid

Cleaning with Citric Acid is very easy. Simply mix the powder (anhydrous) form with water into a 5-7% solution. This should be sufficient for light descaling, removing mineral deposits, hard water stain removal, etc. If you want to try an increased concentration for more effectiveness, a 10% solution may be slightly more effective.

To help the crystals dissolve faster and make a more effective cleaning solution, you may want to use warm or hot water. Also, consider the hardness of the water you are cleaning with. If your water is very hard, you may want to consider using softened water.

Put the solution into a spray bottle, or use a bucket and sponge. This may be used on a variety of surfaces: glass, bathroom fixtures, kitchens, etc. Rinse when done.

How Citric Acid Works

Citric Acid is an effective cleaner for removing mineral and metal deposits in a variety of applications, including descaling, water softening, and cleaning hard water stains. How does this work? What exactly is happening?

Citric Acid is very good at binding to metal atoms/minerals, in a chemical reaction known as chelation. (This might be more accurately described as an attraction.) In the case of iron atoms, the formula looks like this:

Citric Acid 2(C6H8O7) + Iron 3(Fe) = C12H10Fe3O14 + 3H2

Now that the elemental iron is bound to the Citric Acid, it is non-reactive and cannot redeposit on the surface. Additionally, it is soluble and may be washed away in solution.

(Note that, in the case of iron, it will not corrode iron quickly since it is a weaker organic acid.)

Does Citric Acid Damage…?

As Citric Acid chelates metals, it can have an effect on (or micro-etch) surfaces that contain iron, such as stainless steel. Note that the passivation of stainless steel with Citric Acid is a common practice. This is a process in which the iron atoms are removed from the surface of stainless steel parts in a Citric Acid (or similar) solution to inhibit corrosion.

It will also micro-pit natural, porous stone surfaces like marble and granite, as they are made up of carbonaceous substances. Micro-pitting will dull the exterior finish and may make these surfaces unattractive over time and with repeated use. Another natural surface to keep this solution away from? Hardwood floors. A solution can get in the cracks and cause problems over time.

Tile grout is a semi-porous cement that can be cleaned with Citric Acid, but it may eat it over time. However, this is the case with many grout cleaners.

And while it may be used on occasion in textile laundering of clothes, we don’t recommend putting it in a washing machine as it could damage the machine and rubber parts. We don’t recommend using it in your dishwasher, either.

Is Citric Acid Safe for Cleaning?

Citric Acid, especially when mixed in a dilute solution, is generally safe to clean with. However, it may cause skin or eye irritation. For full safety information, review the Safety Data Sheet.

Where To Buy Citric Acid

CORECHEM sells Citric Acid in 50 lb bags. For smaller volumes, try a craft store or your local retailer or supermarket. It may be found with canning or soap-making supplies.