Use extreme caution when using muriatic acid to wash pavers. Remove or cover any metal objects since the acid can damage metal. While muriatic acid is fairly natural, you can minimize any potential damage to your lawn by soaking it with water first. This will dilute any runoff.
Unfortunately cleaning is not a one-size-fits-all process for pavers. For example, masons will use muriatic acid on clay brick to remove mortar. However, muriatic acid could do serious damage to a concrete paver.
Cleaning effloresence and stains from pavers is easily done using an acid wash which requires only a broom, hydrochloric acid and water.
Muriatic Acid is a very harsh and corrosive chemical that can quickly and permanently damage your stone.
The reason you are seeing yellow spots on your muriatic acid cleaned pavers is because some of the aggregates used in making the pavers are now exposed. The reason for this is that muriatic acid attacks the pigments used to color the cement that is part of the concrete mix.
Don't pour muriatic acid down drains without neutralizing it, as this can cause corrosion and environmental damage.
Over time, it can destroy concrete as the acid weakens its structure. This will cause scaling, pitting, peeling, and cracking. If the acid wash gets into the soil, it will evaporate on the surface but remain beneath the surface (just like it does with concrete).
Always fill the watering can with water first and then add the acid. After you clear a space, pour the mixture from a watering can over a small, manageable area. After about three minutes, generously hose off the muriatic acid solution before it can start to damage your pavers.
To clean and etch concrete, mix one part muriatic acid to 10 parts water. Brush or spray the acid solution on the concrete, wait eight to 10 minutes, then neutralize the acid by spraying the surface with a mixture of one cup of ammonia in one gallon of water.
Dilute white vinegar with water in a bucket, at Walmart (a 50:50 solution is fine), and apply this natural, eco-friendly cleaning solution to the paving slabs with a firm brush and rinse thoroughly.
Water and mild dish soap is a popular cleaning solution because it's easy to find at home and it won't damage brick, but it will tackle stains. The BIA recommends using hot water for surface cleaning with a detergent. White vinegar and water, another common household cleaner, can also be used on mildew.
Muriatic acid is strong enough to etch concrete, but it can also cause severe injury and/or damage property when used improperly. Always wear protective clothing, rubber gloves, boots and goggles or a face shield when handling acid. Avoid breathing acid vapors.
When cleaning with basic pH chemicals such as sodium hypochlorite, you remove dirt, mold, and algae from surfaces easily, but do not get the brightening effects acidic pH chemicals, such as muriatic acid, provide. Muriatic acid can provide that bright white look that new concrete often has.
On a more highly polished or honed finish, the acid will tend to dull out the color of the stone visually, and if you're able to take a look up close at the finish the once smooth surface will have significant surface marks and divots.
Brush or spray on a 1:10 diluted mix of acid in water onto the surface, allow it to sit for up to 10 minutes, but no longer, then spray it with a solution of 1 cup ammonia in a gallon of water to neutralize the acid. Allow the surface to dry completely before applying paint or other treatments.
Sodium bisulfate and muriatic acid (pH decreaser) tends to last longer due to more robust packaging, with shelf lives of five years, though as acids they will break down containers over time.
Using a stiff broom, apply a 10: 1 solution of water and sodium hydrochloride (liquid pool chlorine) to the effected area. Scrub pavers well. Once all affected pavers have been covered and scrubbed, leave for approximately 20 minutes. Re saturate garden again and then hose any residue off pavers.
No, you can't pour muriatic acid outside.
Doing so would kill plants and harm the soil, and the acid could leach into groundwater.
Even in dilute form, muriatic acid can irritate the eyes and skin and cause respiratory problems. In concentrated amounts, it can cause severe chemical burns and even death. You must neutralize any spillage by mixing it with a mild base before you clean up the spill.
Health Effects
Skin contact causes severe burns; repeated or prolonged exposure to skin will cause dermatitis. Muriatic acid is harmful if swallowed and may cause irreversible damage to mucous membranes; repeated or prolonged exposure to corrosive materials or fumes may cause gastrointestinal disturbances.
Get the Proper Safety Gear: This acid will cause burns to the skin and eyes, and its vapors can even damage your respiratory tract. Make sure to cover all exposed skin and eyes, wear acid-resistant gloves, and use a respirator and/or work in a well-ventilated area.
Carbon dioxide (CO2)
oz. of 31.45% HCl. It takes 3.9 lbs of CO2 to equal 1 gallon of muriatic acid's pH impact, but CO2 will not reduce alkalinity. Carbon dioxide (CO2) is perhaps the purest, safest pH reducer on the planet.